Billing Issue and No one to speak to

I cancelled my MTN contract in February and went on pay-as-you-go. The last payment I made on the contract should have been in March. I was debited for R1650 on 1 May and I dont understand how this could be as I am no longer on a contract. I have called MTN's call center that deals with contracts. I get immediately kicked off the call because my number isn't a contract number and i'm told I should go the pay-as-you-go call center. The pay-as-you-go call center transferred me to the contract call center and I was on hold for 15 minutes when I finally decided to terminate the call. I have called the contract number and every time I choose the option to speak to a consultant the call drops. This has happened 5 times this morning. I need this isse resolved as soon as possible yet I cant even get through to anyone at MTN