Telkom won't accept cancelations without calling every day for a month

I recently called on to cancel my data contract as I use it once a year, so what's the point of keeping it. I did get a hold of cancelations and supposedly they canceled it, but every day since then they have called me every single day, sometimes twice a day for a month now and while I blame the company for their guerilla marketing tactics, I do blame the sales representatives because I asked them to put me on the do not contact list, and they don't