Vodacom apps a real problem

Some months ago I inadvertently clicked on a link with Vodacom to auto purchase data when my data runs out. This became a MAJOR PROBLEM and took weeks to have them remove it. However about four weeks ago I received an sms stating that the auto purchase was going to take place. Thankfully it did not, but this morning, I get the same message again. I think they did stop it but have not stopped the sms. Its really very poor of them. How can I get it corrected once and for all?