Vodacom has taken money out of my bank account

I have a business cell phone contract with Vodacom. They deducted R2000 extra off my account on the 4.02.2026 (my contract is only for R399 monthly). I phoned to notify them and they confirmed there was ***** off my account, and that they would need some time to sort it out. I received a statement at the beginning of March which states that they have paid me back the amount, however I have not received anything. The call centre tells me that they will keep the money in my Vodacom account and not be paying me back. My monthly vodacom payment will then reduce my monthly amount owing. I cannot believe their business practices!! If I were cynical, I would assume that they have deducted money from countless customers and are using the money to finance their own business. Poor showing Vodacom. How can you just take money out of my account, and when you know you have done this, not pay me back immediately!!