MTN Shocking to upgrade!

I have been a customer with MTN since 1997 and my contract term came to end in the beginning of May 2024 and i have been trying to upgrade the existing 4 contracts with them. It took a couple of weeks to upgrade 1 contract and now we are battling with the other 3. It says my authentication has failed and waiting for certain documents, and then my credit check is approved? it has been a cat & mouse game with this credit check? My agent who is trying to upgrade me has done all my upgrades for the past 15 years and is excellent, and he is also pulling his hair out! Sounds like MTN went on a new system for upgrades which is messing everything up. in the meantime i am paying out of contract rates because MTN can't get things right! My phone never stopped ringing from MTN agents who says they can upgrade you but Can't! Shocking service by MTN, might move to another provider if they don't come right!