Billed for cancelled contract

Hi I recently cancelled my telkom contract and sent through the cancellation form. i was informed it would take 20 days for everything to be sorted out. That was 2 months ago. i have moved to a new address which doesn't have telkom infrastructure and therefore i cancelled. So you can imagine my surprise when i receive a bill from telkom after numerous calls and visits to the Telkom store to get this issue sorted out. This is the second month im being billed for a service i dont have.