No response from MTN

I am not 100% sure of my dates, as I do not have the details with me, but the issue is real no matter what the dates were.

In November/December the payment for my cellphone contract was returned. this was MY fault as I did not trf enough funds to my account. I then immediately made a manual payment. I emailed the proof of payment and waited a few days then contacted them. The person I spoke to assured me that everything was in order and the payment would be app**** to my acc. But that they would move my payment to the next month just to give them time to find the payment. I cancelled the Debit order as I was sure they would make a double payment. The phone was reconnected, and I kept checking on the app, it still showed an arrear amount. This happened in January and Feburary again. The payments were made manually. proof of payment sent to them but the account now shows 3 months in arrears. Today the line was cut again. when I called they reconnected the line but there is still no outcome. I am now 3 months in Arrears and they have not corrected my account at all. When i call they simply say email the docs and wait. this has now been done 3 time and still now outcome???? please please please can someone make an effort to find the money i paid in so that i can go back to a normal debit order and I dont have to go through this every month.