Unhappy customer

I'm very annoyed of the service that I have received from the mtn call centre, on the 26th April 2022 I went to Balfour Park mtn to swap my Sim from contract to prepaid I was told that it is not the duty to do so I should phone the mtn champion, I phoned the Customer care to change my Sim from contract to prepaid day before I bought R120 - 10gig data on the Sim and on my mtn app the was R410 outstanding amount. The lady who assisted me to swap my Sim didn't even bother to explain to me that if my Sim goes to prepaid I will loose my data, it has frastrated me later on when I check my balance then it was R0 balance. I phone the mtn again and ask about the money that was outstanding and have been told that they will reverse the money back to my account I have to send proof of banking details on the email, I have done that but no 1 is communicating with me. I want to carry on with the insurance but I havent given any details from mtn on how to get rich if insurance company. I will never ever open a contract with mtn the staff are not well trained.