Harassment by Onair TV

They continue to harass me at least 3 times a week. Trying to sell me new DSTV decoders. Last year I got the new 3b model, a month later the informed me my decoder was old and out of date. This harassment is on going. If Multichoice wants to communicate with me they must send an email. This has been communicated to them but ignored. I now have more blocked numbers than contacts. D Rouse