From good to trash

MTN has really gone from really good to trash. I have not received an invoice for 4 months I phone in and I am told, "yes that's when we moved to our "new" system". So you guys move to a new system and it doesn't work for 4 months, clearly, there's something wrong there. I then get told your system has not discounted my account properly this month so from paying R148 I have to pay R705, really not on. I go in-store to cancel my account and get told sorry you can't do this here, we don't have access, I must phone 135. Well, I have been on hold for more than 2 hours waiting for someone. As soon as I have cancelled my account I will definitely be porting my number to another provider. The service has become shocking.