PCN times 11.41 for car seen. Your session started at 11.35, so clearly the information for your parking session had not been downloaded to the CEO's terminal at the time of observation. I suppose this is inherent in a system that transfers data from a 3rd party parking application, to a council IT system, that then downloads it to the CEO terminals.
So, of course you did pay, and should submit representations on this basis, including a copy of your RingGo VAT receipt. Don't be surprised if they reject you, but stand your ground; you are in the right and they are in the wrong.