The word useless is too high a praise for the MTN billing department

I have had a contract for 4 years with them. Dutifully paid them without issue for the longest time until this year in July when I changed my bank account and therefore had to change the details with them for the account that they're supposed to debit.

You'd think this would be an easy thing to do- send them proof of the account and then they would change it.

But no.

I have had 6 months of back and forth at the beginning of every month, where I find out that the debit order hasn't gone off, then have to call in to contact centre either because I have been cut off from the network, or because I'm about to be.

So each month since July, I have to call in. Tell them the same story. They check on their side and see that the banking details are indeed correct and verified but the debit order didn't go off. So not my problem at all but becomes my problem because I'm the one who gets cut off erroneously, I'm the one who has to deal with the appalling customer service and I'm the one who needs to spend 3-5 (sometimes 7) hours a month phoning MTN on 135, getting reference numbers, asking them to please not cut me off for something I have not done, trying to get them to take my damn money which is an utterly bizarre concept to me.

I have heard the following appalling responses from staff:

1) each month somebody assures me that the debit order will go off fine next month

2) "the bank account to be debited is closed"- which is nonsensical, because a month before that I had been still having this issue and I had to make an EFT to pay the amount I owed in order for me not to be cut off in the interrim, which I did, and then 2 days later was debited the same amount by MTN (proof that they have my details on their system) which I then had to phone and ask for a refund for, which they paid into my account. (Further proof that they have my details.

3) "someone from billing department will be in touch within 3 days." Hahahaha. Nope. Also, within those 3 days they cut me off unless I bend over to them and pay an EFT which then causes me to have to be reimbursed R1200.

I have absolutely had enough of this utter garbage service. I will definitely not be renewing and upgrading my contract in June 2021, including my business and you will have lost a lot of business from me forever. But until then I DEMAND that you sort this utter nonsensical issue out. I refuse to spend another minute calling your call centre and having to deal with someone who doesn't know the issu and I have to sit and explain it to them 5 times a month.

Sort this out ASAP.

(And then I get sent this (please note, this issue is very much not resolved): Dear Customer,Your query *** has been closed. Please contact call center if you require more information. Thank you for using MTN. Have a Y'ello day.)