Suspended my account, but will not answer calls!

I changed my contract to a prepaid account. After paying the migration amount in store, I was changed to prepaid... Now all of a sudden I receive an sms saying if I don't pay R80.40 my account will be suspended in 2 days. I immediately called the call centre, no answer. I sent an e-mail to customer care, still no resonse to this day. My account was then suspended. I now receive another sms saying I must pay R133.40 or legal action will be take??? What the hell am I meant to do if Mtn will not answer a call or an email, I am trying to understand what is going on, but they will NOT communicate!! And if they cannot take calls or answer emails, who is the only idiot working there that can send out smses asking for MONEY???? Service Provider means something else to these people. I provide the service to there bank accounts and they PROVIDE the trouble!