Unauthorized increase

I had a data contract with Telkom in 2020. It then expired and was renewed without my consent and increased to R149.00. I called several times asking who has authorized renewal of my contract and I couldn't get any answers. I was told, sales are they only people who can give answers. I was promised that someone will get back to me. Till today no one has. To my surprise yesterday, my debit is R259. Again who auth increase to my account?? This is *****, imagine if I didn't have enough funds in my account This can't be happening for the second time.