MTN Unprofessional and *********** service

I paid MTN the outstading amount on June 2021 and accidentaly used PRN as account name and vice verser with account name and the bank details were correct, however the PRN is reflecting on POP. Same day i phoned them to allocate the amount to correct account and they escalated the matter and after a week i followed up it was not done, to cut the story in short it was escalated 5 times and three months later Debt Collectors phoned me and i send them POP ,then gave me the paid up letter. Currently is under CSS collectors. I sent emails to MTN Complaints management ,they had promised to resolve the matter in 21 days but now when I do follow ups, I am told to be patient . I phoned customer service 8 Dec 2021 to check the payment that I made and they promised to allocate the payment and they told me that they have sent to their Team Leader and Managers even today my query is not resolved...