Points that remain to be addressed:
has the flight number changed? Yes or no
your reason for not travelling- wife’s medical condition? Or US entry restrictions?
it seems you approached your insurance company with “US entry restrictions” as your reason for not travelling. Not 100% sure that they’re in the right to not help you on this basis. However, there is extensive mention of wife no longer being able to travel because of medical condition- in which case you need to be explicit with the insurance company that this is the reason you’re no longer travelling
everything else is white noise and important points are being lost in it
try and distil your argument into 2 or 3 short, declarative sentences, and try again