Vodacom - ******** former clients

I had contract with Vodacom (data sim) the contract took more than 24 months but I did not cancel my contract with them because I still wanted the data. When I called last year in March to cancel the contract because I was getting contract from work, we spoke and they tried to convince me to stay. Our call got cut off before we finalize our conversation but I was clear that I want out. the following month they deducted, I called them and ask them to cancel the contract and the person I spoke to told me that it shows that I called to cancel the contract and they will cancel the contract and refund me. the following month they deduct again and never refunded me for the two months. I called them again and eventually received an sms that I have cancelled my contract but month end still they deducted my account, this time I reversed the payment and since then they have not deducted any funds from my bank. Only yesterday that I saw from my bank app that I have an account in arrears and when I went down to the report is shows that it is Vodacom.