Not closing my account

In March I requested my account(and all associated services) to be closed via the call centre, they confirmed that my account had been closed. Then in April I received an invoice erroneously for April services. I contacted the accounts department again, they confirmed for me that my account had been closed and that my account balance was 0.00 and that the invoice of R472.95 was in error and that no further action was required from my side.<br> <br> Now, in May, I have received another invoice which includes the 472.95 from April and charges for May and interest. Please reverse any charges and cancel my account for good and send me confirmation of cancellation. The last time that I contacted the accounts department I asked for a reference number which they said they could not give me but i'd receive an SMS with the reference number, which I didn't receive.<br>