hope you didn't stand there and accept it......most people don't realise that the Nazi has to write it, pin it to your window and photo it and your rear plate. If you can get back, jump in the car and drive off, you don't get the ticket...standing there and arguing is pointless!
If it just fell off your window or dash, you can write to them and enclose it, usually it will be waivered. They are also now expected to give you ten minutes grace as well....
In past 5 years I had two but didn't pay either. One was an area that had just introduced pay and display but I thought was free. Got it quashed. Second was Aldi (only free one hour). Ignored photo and follow up. Nothing happened. Now 6 months later.