Depends on why you got it...
If it's for parking in the disabled space at McDonald's or similar, then go to the restaurant concerned and get them to quash it. Likewise if you overstayed because they were busy.
Similarly, if it was from overstaying due to a big/long-winded purchase at a shop, go to the shop in question and get them to quash it.
If it's because your missus is a bit of a dithery shopper and you were thirty seconds too long, then you could try appealing on the grounds of mobility issues or that the timings are from entering and exiting the car park, rather than the length of time actually parked.
Be warned that the appeals process is carried out by a third party made up from a panel of private parking companies, so you have almost zero likelihood of success...
In my case it was parking in a disabled bay at McDonald's at 2:30 in the morning. The car park and drive thru were closed for cleaning, so you had to park to go in. Unfortunately the company doing the cleaning parked in the only two non disabled bays not in the car park, so I had no choice but to park in one. Incidentally, I was only there 4 minutes. But it took three months to sort because it happened a week before lock down and took three weeks for the ticket to arrive.
Apparently I should have used the drive thru or car park
so my appeal was denied even though in one of the pictures, the cleaning van was clearly parked across the non disabled bays. Trouble is, once the appeal is denied, you cannot reappeal it.
Unfortunately ignoring it isn't an option now. I forget the date, but the legislation was changed in these companies favour a few years ago.