Migration failure - increased package tariff without permission to change

Vodacom is charging me more on my April invoices for the same contract as I paid in March 2022. This after I got a call from them explicitly telling them that I can not afford to pay more.

I also lodged a complaint to their complaints email and the communication went back and forth for weeks. Vodacom eventually agreed to a credit (value not discussed but I would assume +- R2500) which to date has still not been made.