Bad and ********* conduct

I am very much disappointed with the service received from telkom. I have been with them for more than 8 years now. I took a phone in 2023 which the contract ended end of August and since June I have been receiving endless calls to upgrade me and I have made it clear that I do not want any upgrade and that the Sim card should remain prepaid meaning no data, sms's or minutes should be loaded. I hit a shock of my life when they sent me a statement which then state that I need to pay for data. Who authorized for the Sim to be loaded with data? Is there a sign or voice contract which I accepted? Whoever loaded those is ********* and has breached the process. Next thing if u decide to reverse the debit order I will be charged a penalty. Someone needs to account for this because I never accepted this. I will not be paying for a service which I made it clear that I do not need anymore