@Pauline ******
I expect that the airline will stonewall you hoping that you will disappear over time. Now is the time for UK261. Once you have submitted the UK261 let the airline know as that may get them to revise their position. Another cheeky option is to go straight to the inbox of the CEO. There is a prominent site for many CEO email addresses (won’t post the link here) it will be intercepted by one of their execs who will give it the due attention. Good luck.