Same thing here.  Calling my new cell phone from the beginning.  Wondering if it is something from T-Mobile???

I am Albanian as well and I have the same issue.
They call me three times a day and almost every day.
I called them back and asked what company name is this and the name of the person I was talking to and he hung up.
  Also in the greeting message you hear when you call them they don't mention the company name which is strange. They just forward you to a representative.
  All I can think of is that this is some kind of verification service.
Where they call people and check which number responds and which doesn't.
  Then maybe they pass this info to companies who call only the phones that respond with offers.
This is just a guess.

Here is what I found:
tnID Database Record For 617-826-6113

Caller ID:  Current Telephone Company:

Original Telephone Company: Mci Worldcom Communications Inc. - Ma

Original Telephone Company Type: Competitive Local Exchange Carrier (CLEC)

Estimated City: Belmont
Estimated Region: Massachusetts
Estimated Postal Code: 02178
Equipment Location Code: BSTNMACODS6

This I believe is a long distance provider. You are their client.

Unwanted calls from the above number 617-826-6113.  Looking for Albainain speakers.

I called them back the person who answerd my phone call was Albanian. I asked him nicely"please erase my number from your book and he didnt answer then I called him back in english version and asked him again to do the same and he replied rudly ok understood. WTF is that going crazy, every single day I received 3 phone calls from them diffrent time of the day, please help by taking care of this number