Telkom Extremely bad service

I had ordered a Telkom LTE Router from Telkom and was not happy with it as it was eating all the data very quickly. I returned it to Telkom and requested a cancellation within the prescribed time of a cancellation. This was in April of 2017. To date they are still billing me and when you get through to the call centre they transfer you to various departments and give you case numbers but you cannot directly speak to the cancellation department as they only work with email amongst themselves. They now owe me over R 2500.00 and how I am going to get my money back, I don't know. The service you get from them is totally disgusting and most of the agents don't know what they are doing, they go by the book and you cannot get to speak to any supervisor as they are always busy. WHAT NOW. Not a Happy customer