Consistent decline of service from Mtn

I would like to take a moment to express my frustration with Mtn regarding the manner in which I was billed during May and June, 2020. I am a contract customer of Mtn and I have been so for the last 20 years. As per usual with my contracts, I sign a 24 month contract and agree for Mtn to bill me monthly, the current contract that I am on means that I am billed R1099 on the 1st of each month. To my horror, I was not billed on the 1st of May, 2020 but rather the 4th of May, 2020. This isn’t a major problem, however on the 4th of May, I was billed R2198 (a double premium). This ultimately led to an unpaid fee from my bank, but the most annoying aspect of all this is that on the very same day Mtn refunded the full amount. Things got more annoying when after a week, Mtn did not even attempt to debit my monthly payment. I had to call in to make arrangements, only for them to tell me that my account is overdue. Anyway on the 15th May (after making the necessary arrangements), I paid a double payment (in an attempt to never have a repeat of this scenario), which to any normal person would mean that on 1 June, 2020 my account would be in credit. No this was not the case, the incompetence at Mtn continued with an agent calling me about a week ago to inform me that my account is overdue by R2198, the very same amount that I paid on the 15th May, 2020. I explained this whole long story to her and thought that this was finally over. Yes, you guessed it, the incompetence at Mtn continued, and I was billed again last night for R1099. What a poor reflection of quality service and that of prolonged incompetence, especially during these financially devastating times we all find ourselves in. Please may I receive assistance from someone (anyone) at Mtn who is even fairly competent in resolving this matter, and especially help refund my unpaid bank charges as this is not my fault but rather a reflection on the declining quality of service that one has become accustomed to of late from Mtn, as well as some of it’s staff that simply cannot do their jobs efficiently.