Even I had faced same problem with one of the leading CDMA operator. Finally I registered my mobile number with DO-NOT-CALL Registry by sending a SMS. Since then I am not getting any spam/unsolicited calls/SMS from service provider. Each service provider has different SMS number. for example reliance CDMA user has to send SMS DNC DEACT to 23733. Within 45 days they will stop unsolicited SMS and calls. Its highly effective. If any anybody wants for other service providers, pls mail me your email id at surenderu@rediffmail.com, will forward you pdf file which has numbers for all service providers.
