They state that they are from Cardmember Services (leads you to believe it is your own credit card company)and they offer to lower your interest rate.  Press "1" if interested.  When you ask them to provide the name of the company they represent or any other probing questions they hang up.  When you ask them to cease calling and take your number out of their data base, they hang up.  When you call the #, you get a recorded message "Your number can not be completed as dialed".  When you *69 you get a recorded message "We're sorry, the call return feature can not be used on the last call you received".

just received offer "to consolidate credit card bills at much lower rate" -
My number is on DO NOT CALL -
207-494 2*** comes up with references to the telephone company "BROOKS FIBER COMMUNICATIONS" in Portland, Maine.  A search for this company brought up many complaint including
http://mainegov-images.informe.org/mpuc/orders/1998/98758ni.pdf
- which is:
-----PUBLIC UTILITIES COMMISSION
-----NOTICE OF INVESTIGATION
-----Investigation into Use of Central
-----Office Codes (NXXs) by New England
-----Fiber Communications L.L.C. d/b/a
-----Brooks Fiber Communications
Docket No. 98-758 - dated October 6, 1998

this is clearly a problematic company/marketer who deals with an equally problematic phone provider.

I just got a call from 207-494-2485 that was a recording stating that they were calling about my credit card and could offer me a lower rate.  (I don't own a credit card).  I pressed 1 to talk to someone and they gave me the speech.  They said they sent me out a letter that I did not respond to.  I said I didn't get a letter, they insisted they sent it.  I asked for the company name and phone number.  They said Card Services and gave me 1-800-452-3987.   I told them I didn't have a credit card and I was on the do not call list, they  hung up.
I called the toll free number to get a recording that said they had a new national directory assistance service and to dial 10 15 15 800.  I then searched the web for that number and found it to be a number charging $4.99 a minute.  
So, I'm assuming this is a scam.  I've had my number long enough and been on the do not call list long enough that they could not have called me by mistake.  I'm also going to report this to the attorney generals office.  Be warned, do not give any information to this company.  I'm very sure it's a scam!

Got a call from 207-494-2485 tonight. I did not answer it. Tried calling back the number, it is disconnected.