MTN - Overcharging

I have been having an issue with MTN overcharging me for the last 3 months and I have been trying to contact them to resolve the issue but every month they say I have to wait and they are aware of the problem but they keep overcharging me the next month.

My MTN contract number is ***. The contact I have taken out was a "MY CHOICE 40GB" that costs R199.00 including vat. I have taken out this contract with MTN in March 2021.

For the last 3 months MTN has been overcharging me, R955 in June and R1279 in July and August and every time i call them they say they escalating the issue and till now they have not done anything to rectify this error of theirs and its affecting me as i am unable to afford this amount.

And its not like they can say my over spend limit is what is causing this amount to be so high because I checked and its been on R0.00 .

Whats really frustrating is that every month for the last 3 months I have been calling them and trying to resolve this and they haven't made a single effort to help me out.