Contract not cancelled

Good day, I have settled my account and have done everything as instructed to cancel my account. I was advised 24 hours (Your reference number is EC-04QZ-2IOZEQ.) - this was Monday. To date nothing has happened and the call centre remains unhelpful as ever. What does a person have to do to receive service. All I am asking for is for the service to be cancelled and for the line to be made prepaid.