SB - Cash finance charge

Hellopeter Community, I am sad to be experiencing this with my former favourite bank Standard Bank, there is now a new credit card charge, not communicated EVER, called cash finance charge which now activates when the credit card is used to purchase Fuel and any electronic card account purchase or transfers. I mean UCount rewards require credit card purchases but now we get penalized for it... Is this even allowed without prior communication or can a service provided just update usage terms and consequences at their own discretion?