Unacceptable treatment of loyal customer

I am a loyal customer to MTN and have been putting off writing a bad review for months now, but I had the final straw now. Due to incorrect invoices in the past, I opted to pay with an EFT for my 5 contracts with MTN. This worked for several years until May 2020. Suddenly my invoices shows that I had not made any payment, although I make my payments regularly. I tried to sort this out through the call center and various emails, without much success. Everytime they claim it is sorted, the next invoice comes with the same problem. Now due to this, I became uncertain as to what amount to pay.

-On the 19th of July 2020, I received the latest invoice and statement which was still not correct. I again queried this without any response. Payment is due on the 2nd of August 2020. -On the 29th of July 2020, I received a payment reminder which indicates that I have 10 days to pay. -On the 30th of July 2020, MTN cut of my telephone lines without any warning whatsoever.

In the meantime, I am connected again, but there is still no confirmation as to what is going on with the account.

Now this for me is really unacceptable as I require my cellphone for business purposes and lose money every minute I am not connected.