I had the same problem with these sleaze-bags. I am on the national do not call registry and I reported the violation. These guys are obviously trying to work around this list.
I finally got a easy way to stop the calls. I called 877-646-7319 last week. They had my phone number removed from the callers list and I haven't gotten anymore calls.
I called the 877-646-7319. No help. I called AT&T and the only thing they could do would be to charge me $5/month and then I could block the call. I can't believe these f-----'s in Podunk, RI can get away with this!!