MTN Worst service ever

MTN has gone from excellent to the worst service ever in South Africa, I have 3 contracts with MTN for a very long time, My number is ***, This is my issue, My contact was due for and upgrade in November 2020 to which I have received many call from MTN agent to upgrade but always said no, as MTN retention department normally calls and gives me a good deal as an old customer, So on Friday 20th November 2020 a lady from the retention department called with and excellent deal which I accepted and while trying to process the deal she could not because she said there was a contract already pending which I know nothing about she then cut the call with a promise to call back which never happened, So from then to now which is almost 4 months I have call MTN more than 40 times and it take 30 to 40 minutes to get through to the call centre and about a hour and hour to get to retentions, The agents are so bad at their jobs they cut calls or put on hold and then cuts, When you get and agent that has some understanding and get a reference number it doesn't work now they are billing me R1700.00 a month for a problems which they caused and failing to solve, they don't know what they are doing. I'm truly feed up...