Cell C is being *********

I cancelled my contract on the 2nd January, giving Cell C 30 days, even though January has 31 days, my contract was cancelled on the 2nd February, which is already incorrect, nevertheless, I paid the January account and I paid the February account, as you pay in advance which I did, now all of the sudden I need to pay another R831 ...... for what for another months cancellation. This is not going to happen. I did what I had to do. I will pay for ONE day in February, not the entire month !!!!