STOP CALLING ME!!!!

So please explain this to me. I have been receiving pestering calls from vodacom to upgrade my contract, in the order of up to 20 calls a day. After answering some of the calls and telling the operator i do not want to upgrade. Then phoning vodacom and asking them to remove me from marketing regarding new contracts and upgrades. Now I am receiving even more calls, and even smses and whatsapp messages asking me to upgrade my contract. *** vodacom. Are you completly useless to do the exact opposite of what im asking