I use a CPR Callblocker. Every solicitor/scammer has one chance at me, then never from that number again. A phone that used to host several unsolicited calls a day now allows none for weeks at time.
http://www.amazon.com/CPR-Call-Blocker-V108-Telemarketing/dp/B004BTVQ5E/ref=zg_bs_172612_10
So do I but they keep changing their phone number. The "credit fixer" call message always starts with "this may be your last chance..." If only.