Cancellation not activated

Having decided to close one of our small businesses, I emailed Telkom on 17 February to cancel that phone line as from 28 February. I was sent an automated response to take ID and the letter to a Telkom service centre to complete the process.This I duly did on 22 February. The consultant at the PMB branch was very helpful, and duly faxed all the documentation to cancellations. At the end of March we paid the account for outstanding amounts due, and assumed that would be the end of that. We happened to move premises at the same time, and no further calls were made from this number. Having received another account now billing us for 'subscription services' for the following month, I tried to phone 10217 to sort it out. I waited for an hour on this line to speak to a consultant, and then gave up, as it was blocking incoming calls. What more can I do?!!!