Cell C bad service ever.

I got a call from Cell C offering me a cell phone contract which I took because I needed a phone. They asked me when is my pay day I told them it's the last day of the month and to my suprise they decided to debit on the 25th of November which was the first debit order. I queried and paid manually after 10 days after I have paid they debited again same amount that I have paid when I call to enquire as for why they said they did not see. Again for December they debited on the 24th after I told them to change my debit date. They are telling me that they debited on the 24th because on the 25th was a public holiday meaning regardless of me changing the debit date with they were adamant to debit on the 25th. They did ask me where do I work and I told them I am working for Government which doesn't change the pay dates for us. And now they are charging me penalty fee for their mistakes. Worse service ever from Cell C I really regret taking the contract phone from them.