MTN refuses to refund my money they have ******

Since last year July I have been fighting trying to get my account sorted. For 5 months they deducted my normal premium plus an extra R330 there is an error message on my account which shows a rejected amount of R330 which "justifies" them to deduct this amount on top of my monthly payment???? I have tried every month since July 2023 10 Months to sort this out all they do is open a ticket and then close it and if I am lucky they send me a 1 liner email to say "the reason why we charged you extre was because of a rejected payment". So please help me with this logic, my normal account is R650 the "rejected payment" is R330 so if my bank statements which I have supp**** now 3 times shows my successful monthly payments how is that only R330 from the R650 is rejected?? I have been a loyal MTN customer for over20 years and I am utterly disgusted by this service that I am experiencing over the last 10 months. This is my last attempt to get this sorted.