Cant get Telkom to cancel my contract - NO RESPONS

i have called the telkom call centre in December to cancel my cellphone contract that expired in Oct/Nov. I was told that i had to complete a cancellation form and email it back to the relevant department, which i did on the 28 December 2015. When i phone a week or two after that, the consultant at the call centre, that i had to wait 21 days in order for them to respond, and after the 21 days they will contact. I have not been contacted too date, and when i received my bill end Jan 2015, i was charged double for the for relevant contract deal i had. When i phoned last week, the consultant again told me that she is forwarding this matter to her manager and he will contact me within 24 hour, another week has passed and still no response this is very irritating, and no at a telkom store can assist, you have to work through call centre for account related queries,Why i don't know!!!Bad customer service,