Non stop SPAM from Telkom with no option to stop them

Telkom has been sending me spam messages every time I opt out, it takes money every time I select STOP, however, the messages haven't stopped at all. The call centre is terrible, they are clueless and helpless and once named Thabile from the Durban call centre hung up on me. Why do they need my ID number to stop Spam messages from Telkom when didn't even opt in?