Mike, you can report unwanted calls to the do not call registry at https://complaints.donotcall.gov
Unfortunately it is difficult to prosecute unsolicited callers unless it gets to the point of being abusive, due to the "freedom of speech" clause in the 1st amendment of the US Constitution.
I think it has more to do with the fact that not enough people register complaints about these unwanted calls. Even for me it is difficult since the majority of the calls are automatically blocked. Top that with the operations based overseas.