Still being Billed for terminated contract

I cancelled my contract in July due to horrible customer and network service. Since I had my contract, my device was faulty 3 times. Each time I had to drive out to them to hand in the device for replacement or repairs. Eventually after way too many trips to the Neotel store in Cedar Road, Fourways, they agreed to cancel my contract. Guess what, it is now September and I am still being billed for a non-existant service. As usual, no one answers the phone at the actual store and if I phone their customer care number I simply get transferred from one agent to another. I wonder if I will get refunded for these charges.