Cannot upgrade online with mtn during covid time

I've got my contract for a very long time...Im due for an upgrade and I've tried numerous time to upgrade online without luck. Especially with covid I don't really want to go to the store. I initially tried during the Black Friday sale. Numerous times.. I was kicked out the system and I called numerous times without much luck. Two weeks ago I tried to upgrade again online and again it kicks me out. I called customer care and they refer me to a 3rd party company. After calling more than 5 times and waiting more than 15min I Dont know what to do?

I then called customer care again and I told them I wish to upgrade as per the Black Friday special and they cannot help even though I had a reference number for the application.

Help any one