Horror service from mtn

Been a customer for 15yrs paying contract religiously don't count for anything. Took a 2nd Sim only wifi contract in Dec, continued paying paying my contracts. I get 50gb every month and I use only that 50gb and switch to telkom. April, I get a 4000 bill from mtn, from where I don't know, tried to call mtn for enquiries, don't get straight answers, everybody I talk to gives me their own version. I know for a fact that I don't go beyond the 50gb as I always check the balance. My child is at school the whole day, me and my husband are at work during the day, there is no one in the house. May another 4000, no answers from mtn again. I know that covid has put us through some tough times but I can't be ********** by mtn. I decided to stop my debit order and pay my contract in cash every month. I'm paying my usual 900 contract every month. Now they decided to suspend my lines, I don't know why they are suspending my main contract as it's not in arrears I'm continuing to pay it, if that is not bullying, I don't know. I'm just tired of mtn, I'm done with it. There is no loyalty to loyal customers. It's one hurdle after the other with mtn, don't know why I tolerated so long.