what has your normal annual fee been for what size unit? what is the reason for the SA? damage that ins didn't cover, routine replacement, or extraordinary items? replacement/maintenance/normal refurb should be accounted for in annual dues contribution to reserves and if it's for that, I'd be concerned. Or the annual fees were just too low and they had a reality check. I'd also look at last year's budget and see what defaults were.
OTOH, my former resort had to redo sewers because of new city ordinances. They also put in elevators (we had only stairs) at the same time. Those were both extraordinary items and the elevators were a significant upgrade. Our assessment was $400. I was fine with that. Since you've owned for years and, I'm guessing, never had a SA, I'd be inclined to pay it and keep enjoying. Or you can pay the fee and then try to give it away on TUG for free.