Sharing personal information to unsolicited insurance companies

I keep getting phoned "on DSTV's behalf", by companies marketing insurance products to me. I have on numerous occasions requested not to be phoned, and block every number, however they persist. I have now contacted DSTV through their chat service, but the feedback is absolutely useless - their advice is to tell the agents phoning that I don't want to be phoned. DSTV is meant to be a premium service, however they share personal information to companies for unsolicited and continued personal marketing of unwanted products. Utterly disappointed.