Mtn service is non existent

I did an upgrade early 2022 Because Mtn changed their debtors system I was given a new account number without being informed I subsequently paid R4000 using the old account reference and have been struggling for more than 6 months to get this to be transferred to my new account. I have been to Mtn 5 times and received a reference number but the ticket is closed within a week with no communication. This is the most useless organisation bar none I am sure that government departments provide better service than MTN South Africa