Vodacom is penalizing a fee of R100 for settling my bill earlier, it does not make sense

I thought settling a bill earlier than debit order date was a good practice and service provider appreciates it until i met vodacom that is now penalizing me a fee of R100 for settling a bill earlier. Can't wait to terminate my contract. No matter how the consultants that spoke tried to justify it, it will never make sense. 😏