Account cancelled

I cancelled my internet contract with Telkom in Feb 2015 within the allowed days I have to cancel. It was logged at the shop and all goods were returned. Telkom is claiming I owe them money and have handed me over to debt collectors VVM Attorneys. I went back to the Telkom shop to get proof of the cancellation and forwarded this ti vvm. Nothing has been done and it has been 2 weeks. I had to call a manager to take the case further as no one seemed to be interested in righting a wrong! Vvm now claims that I have made an arrangement to pay which by the way I never did. I refuse to pay for something I do not owe! I want a formal apology from Telkom and my credit rating fixed! SORT THIS OUT PLEASE!!!