Billing for settled contract

Dear Cell C

I paid up my contract on the 11th of October yet I will still be billed for it on the 24 - what it the actually is happening? It took me more than 10 calls to settle the account and send the POP yet the update was not done? I will not have my money taken without my concern and I know this won't be refunded I will be told it will be allocated to the upcoming months. SORT THIS MESS OUT!!!!!