***** contractual terms

I have been on a 24 month contract ( Red VIP) paying R1,400 per month for the line and not for the handset. I took the contract in 2022 June. To my surprise yesterday they debited my account with R2165,54. On enquiry this morning they say it is because I am now on a month to month contract with is absolute *******. No warning of the change of debit order nothing, they just went ahead and debited the amount they wanted to debit. Even if I’m on a month to month contract what would make the debit amount to change? This is absolute nonsense and it is ridiculous and of course downright unacceptable!!!