Poor service

Good day

Very frustrated and disappointed. I went to the MTN in bayside mall in the beginning of the month of june to cancel my contract and move over to pay as you go. I was told I could only do it once the contract has come to an end. This month I had to pay the full amount again of the previous contract terms. And I could not make phone calls and had to load airtime. How is this possible that an I get billed for an open line but still have to load my own airtime . Upon phoning mtn to find this out I was told that there is no cancellation on the system or migration over to pay as you go. Someone needs to sort this out and phone me.