Cell C Overcharges but does NOT refund

So I cancelled my Cell C contract on the 9th of Sept 2018 and was still made to pay for October, but the promised they would refund October as per their email below:

"As per our telephonic discussion, the contract line ( ********** 602) will be permanently deactivated on the 09/10/2018. You will be charged the full subscription end of September 2018 and a disconnection credit will be allocated in the month of November 2018. Please note that any out of bundle usage encountered in September 2018 will be billed and charged for in November 2018."

It is now the 4th of December and do you think I have received a refund. Not a chance, you bunch of ******. You are so quick take a persons hard-earned money but then you don't have the decency to refund and an overcharge.

This service provider should be avoided at all costs...