"Parking charges are extortionate for 25 mins"

I'm happy with the care and attitude off the staffI however the parking is terrible, I had no change so asked reception they advised you can pay later, meaning I have to go back whilst feeling unwell, then seen that I could do this by an app. I was not told by staff or the info in the carpark that it's an extra 30p for doing it on the app. Also I have been there 25 minutes, 5 minutes over the free period then forced to pay for 12 hours. So effectively you have charged me £3.30 for 5 minutes extortionate especially when I have not recieved the help I need and been referred back to GP I tried GP first but they had no slots available which is why I came to the walk in, in the first instance