Vodacom refusing to cancel my expired contract

I asked Vodacom to terminate my phone contract ***) in May 2025, and again at the beginning of July 2025 but they keep on debiting my account R524 per month. I have spoken to them on the phone, sent email and went to Vodacom shop. I have screenshots of my communications with Vodacom. They debited again now in September. I want refund. I decided to cancel the contract because i cannot afford it anymore. Why are they bullying me like this?