Unfortunately it is no longer illegal in US for telemarketers to call cell phones. Legally, there is no recourse. The only thing to do is not answer, if you do not recognize the number. There is the cell phone do not call list, but this is not something that is enforced. It would be almost impossible to do so.
(206) 858 - 8575 just called me, and since I was just getting out of the shower, I unfortunately answered it, B4 checking it, because I am expecting a call from My MoM.