FRUSTRATED WITH MTN

I have had my contract with mtn for years now. I upgraded in may 2020..But for some reason mtn cannot see my eft payments i have made since october 2020.i have never skipped a payment. I have been paying the same bank details for over 2 yrs.. I sent all proof of payments made in december and mtn is still failing to resolve my query instead they suspend my line every 2nd week. Is it really difficult to allocate payment honestly.