Halston Financial out of Austin,Texas area. Very rude,very short tempered person I dealt with. Tried to get me to pay for an ER visit from over 2 years ago that my insurance (Mediacaid) is responsible for. Not sure if this call center or business is an actual scammer,but definitely unpolite!

The only one I can find is this company in Austin Texas, lists an address in a residential area.  Not much on them, claim to be in business 7 years, but no BBB page.http://www.manta.com/c/mx4f111/halsted-financial-services.  I can't find a registration for them which would mean that they are not legally allowed to conduct business.  In any case, since you talked to them, they must do the following by law:
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.
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

Great information. Thanks

Just got a call from this number. Readout says Nextiva Inc which is a communication co. Must be a sales call.

Unwanted call