Payback my money MTN

I have been trying to solve unauthorized debit orders from MTN. I upgraded in March. In May MTN sends me a message saying they haven’t been deducting the insurance money and they will take it all at once on debit order date. But in June they took almost double the amount agreed on my contract. It bounced and they cut off my phone. I went to the nearest branch and was told I missed payment. I told them they were trying to deduct more than we agreed on on the contract. I then made arrangements for payment for June in July. The debit didn’t go off. I called and checked but was told it went off. Two days later my phone is cut off again. I went to the branch again and was told I missed payment. I knew because the debit didn’t go off. I made the payment at the branch and my phone was eventually activated the following day in the afternoon. Then I realized that there was also money debited from my account after I made payment at the shop, the same amount. I went and enquired and was told to submit my bank statements which I did and still not refunded. When I went again was told the money is insurance for my previous contract phones and I have to call insurance and cancel (which I did) Now yesterday the same amount of R2071,64 went off again from my account.