As you can see blocking there numbers will not be an option since they have plenty of spoofed numbers they call from.  Since they left a message they are now required by law to do this (it seems they don't like to though):

Federal law (FDCPA) requires them to send you a letter (US MAIL ONLY) within 5 days of their first contact that contains their name, physical address, the creditor’s name, and the amount of the alleged debt.  It also must contains “mini-Miranda” telling you that it is an attempt to collect a debt and that all information will be used for those purposes.  The one other important thing that this letter must also have in it is that you have a right to dispute the debt within 30 days of receipt of the letter and if you do so, all collection activity must be stopped until the debt is verified

Then:

You need to send them a certified, return receipt debt validation, cease and desist calling, or "not me" letter (think of it as the best $6.47 you ever invested).  You also need to report them to the proper agencies to which I have provided links to.  Then you need to go out and get a consumer lawyer to sue them on a contingency basis (no money out of your pocket) and let them pay you for the harassment.  If everyone did these three things, these crooks would be bankrupt and we would all be the richer for it.  Use these web sites to find an attorney in your state that will probably take the case on a contingency basis (no money out of your pocket up front):  http://www.consumeradvocates.org/
http://www.consumeradvocates.org/find-an-atto ... tates_value=All

CONVERGENT OUTSOURCING AKA CONVERGENT RECEIVABLES MANAGEMENT AKA CONVERGENT RESOURCES AKA ER SOLUTIONS
Posted In:  http://800notes.com/Phone.aspx/1-208-779-3248
http://800notes.com/Phone.aspx/1-202-808-7200#p836428347616898904
http://800notes.com/Phone.aspx/1-855-285-5160#p850980769580877291
http://800notes.com/Phone.aspx/1-303-214-0774
http://800notes.com/Phone.aspx/1-949-777-5501#p868226418882302566
http://800notes.com/Phone.aspx/1-949-333-0685
http://800notes.com/Phone.aspx/1-312-379-8674
http://800notes.com/Phone.aspx/1-817-585-2568
http://800notes.com/Phone.aspx/1-505-348-3281
http://800notes.com/Phone.aspx/1-702-583-3532/2#p884317818524420853
http://800notes.com/Phone.aspx/1-614-607-6950
http://800notes.com/Phone.aspx/1-305-894-1112
http://800notes.com/Phone.aspx/1-410-864-3253
http://800notes.com/Phone.aspx/1-877-495-1261
http://800notes.com/Phone.aspx/1-603-263-7048
http://800notes.com/Phone.aspx/1-603-263-7097
http://800notes.com/Phone.aspx/1-206-777-1953
http://800notes.com/Phone.aspx/1-469-265-3058
http://800notes.com/Phone.aspx/1-800-903-2319/9
http://800notes.com/Phone.aspx/1-215-220-4748/2
http://800notes.com/Phone.aspx/1-323-331-9683
http://800notes.com/Phone.aspx/1-916-431-0748
http://800notes.com/Phone.aspx/1-713-496-3832/3
http://800notes.com/Phone.aspx/1-502-654-6254
http://800notes.com/Phone.aspx/1-323-331-9693
http://800notes.com/Phone.aspx/1-800-903-2319/10
http://800notes.com/Phone.aspx/1-215-220-4743
http://800notes.com/Phone.aspx/1-877-606-6900
http://800notes.com/Phone.aspx/1-410-864-3254
http://800notes.com/Phone.aspx/1-770-870-1056
http://800notes.com/Phone.aspx/1-469-265-3049
http://800notes.com/Phone.aspx/1-800-423-9397/3
http://800notes.com/Phone.aspx/1-803-740-3319#p1043664252132464947
http://800notes.com/Phone.aspx/1-757-985-3425#p1055193203663216503
http://800notes.com/Phone.aspx/1-617-766-5340#p1058908149119430594
http://800notes.com/Phone.aspx/1-215-220-4591

I have to wonder why a “legitimate company” would need so many different phone numbers to conduct business.
Web site lists no contact info, but lists the name as Convergent Receivables Management:  http://www.convergentusa.com/contactus/contact-form.php?d=4
Ok, this is a strange company record.  According to their web site, they are located in Atlanta, Ga and have been in business since 1955.
Now the BBB gives them an B rating with 1053 complaints (The BBB removed 117 complaints so that they could upgrade them from an F to a B) and 44 negative reviews and a notation that there is a pattern to the complaints-namely that they routinely violate Federal collection laws.   They also say that the business was established in 1950, that they are headquartered in Washington State, and that they are registered with the Washington Dept. Of Revenue: http://www.bbb.org/western-washington/busines ... enton-wa-501066
So if you go to the Washington State web site and look up their corporation, it indicates that they were formed in 2013:

CONVERGENT OUTSOURCING, INC.

UBI Number    603319184
Category    REG
Profit/Nonprofit    Profit
Active/Inactive    Active
State of Incorporation    WA
WA Filing Date    07/22/2013
Expiration Date    07/31/2015
Inactive Date
Duration    Perpetual
Registered Agent Information
Agent Name    CT CORPORATION SYSTEM
Address    505 UNION AVE SE STE120
City    OLYMPIA
State    WA
ZIP    98501
Now that is the corporation that is active, the other corporation with that name is inactive but was owned by the same person:
UBI Number    600059082
Category    REG
Profit/Nonprofit    Profit
Active/Inactive    Inactive
State of Incorporation    WA
WA Filing Date    01/11/1972
Expiration Date    01/31/2014
Inactive Date
Duration    Perpetual
Registered Agent Information
Agent Name    STEVEN J HUNTER
Address    800 SW 39TH ST
City    RENTON
State    WA
ZIP    980579004
Special Address Information
Address    PO BOX 9004
City    RENTON
State    WA
Zip    980579004
Bizapedia has them as forming in 1972 and still active, although that date would apply to the inactive corporation (confused yet?  I am):  http://www.bizapedia.com/wa/CONVERGENT-OUTSOURCING-INC.html

The following are complaint sites:
http://www.whoscallingnotes.com/listings/puget-sound-energy/800-772-1169/     Some say that it is the electric company, but there are posts that say they have no account with them.
http://www.ruscammer.com/8007721169/index.html    this site seems to agree that it is a scam
http://www.privacystar.com/lookup/800-772-1169    this site claims it is Convergent Outsourcing
As does this one:  http://www.fschulmanlaw.com/800-772-1169.phtml
But I would say the proof is this Chamber of Commerce page that lists these criminals in Washington and has that very same phone number listed for it:  http://chamber.gorenton.com/list/member/convergent-outsourcing-inc-1299
•    Collection Agencies
Convergent Outsourcing, Inc.
800 SW 39th Street
Renton, WA 98057
(425) 562-9720
(800) 772-1169
(206) 340-4003 (fax)
Description of the business from Hoover’s:
http://www.hoovers.com/company-information/cs ... 80233d315d.html
“Convergent Resources strives to avoid a divergence when it comes to collections. The company and its subsidiaries provide accounts receivable management, collection, and customer care services to a variety of industries throughout the US. Clients include banks and financial institutions, retailers, utilities, and telecommunications, cable, and satellite providers. Its Convergent Revenue Cycle Management division offers health care industry collection services to hospitals, helping them recover payments from insurers and other creditors. Convergent Outsourcing provides consumer accounts receivable services. Convergent Commercial is a commercial collections agency.”
.
Read up on your rights here, get template letters to send and also make a complaint at this government site: http://www.consumerfinance.gov/

Also file a complaint with your State Attorney General's office.
List of State AG’s offices:  http://consumerfraudreporting.org/stateattorneygenerallist.php
As well as the Washington State AG's Office:  http://www.atg.wa.gov/
and the Washington State Department of Financial institutions:  http://www.dfi.wa.gov/