Account not debited

I'm very angry with Cell C how they treat customers is absurd. Last month my account was not debited and I laid a complaint where they phoned me once and I was at work and couldn't answer the call. They decided to debit me R270.00 whilst my contract with them is R249.00 and kept on debiting I incurred bank charges for insufficient amount. They then stopped and debited me on the correct date but R340.00 which are charges that I was trying to avoid by telling them they didn't debit my account. Again after that I'm still not debited for April and I again am following them around to debit my account. This is incompetence and annoying