NO SERVICE FOR UPGRADE FROM OCT 2023 TO DATE FROM MTN

I have been attempting to liaise with MTN since october 2023, to increase my credit limit so that my upgrade can be auctioned, i have spent numerous hours on calls to MTN, only for my calls to be cut, or for me to transferred from one call centre agent to the next. This is absolutely crazy, time consuming and costly to me as I wait up to 18 minutes a time to speak to a consultant, only for the call to be cut once they answer. I have been directed from Mondo to MTN call centre's and back again Can MTN please sort this out, the service or lack thereof is atrocious. This has been going on since october 2023, i have all of the emails confirming this.