That’s really frustrating.
Paying extra for exit row is pretty much just for the legroom, so if they move you to a normal row, what exactly did you pay for?
Plane swaps happen, sure, but refusing a refund after that feels wrong. Especially when crew onboard just tells you to deal with customer service later.
I’d definitely push again. Maybe escalate it or try through a different channel. This seems like one of those cases where you should at least get the seat fee back.
Also get the Ryanair comment… but stuff like this is how people start reconsidering.