C Fibre not crediting money they owe

I ordered a fibre package with c fibre, which I had to pay for in advance. This was done on the 27th of August. Then, on the 28th I cancelled the order, in writing, as i received a better deal somewhere else. I also had an existing package at another address that I cancelled a full 32 days in advance. Even though I received a confirmation of the cancellation, they still deducted the money from my account at the end of the month. I have called many times since then, but my money for either of these is not forthcoming nor have they contacted me. It is over R3000, which is not a small sum of money for the average consumer. I would strongly recommend to stay away from this ISP