Random debit order mid month

Telkom doesn’t have the best customer service accessibility. We need to talk to human beings and we don’t have much access to that. R830 was debited from my account randomly. I have a contract, but why deduct so much money mid month. My account has been in good standing, why break the trust now. I have been happy for the last 5 years, but one bad service could be enough for a client to leave