extremly bad service practice

i recently upgraded my cell contract at an mtn store in the Nicolway shopping center. I upgraded tge saturday and the following day my sim was suspended. I drove back to mtn the sunday and the said this was the sim card that needed to by swopped.to a nano sim but i had to drive to fourways mtn as they didnt have stock. I did this and come monday my sim was still suspended. It took me 26 call attempts and 4 hours to the mtn call centre at 808 before i could get hold of them. They said that my new contact amount pushed my monthly installment over my credit limit. They said they will escalete this to the creditors department to have the limit increased and activate both my cell contracts. I phoned in two more days and each time was.told this is.escaleted again after holding on for 30 mins. This still has not been sorted. I called in a final time more than a week later and was told i cannot speak to the creditors department as they are not taking any calls due to a backlog of.emails. I checked my mtn active credit details today which is 3 weeks.after they turned of.my sims without notice ans still my credit.limit has not been corrected. Up till now noone has called me!