it's unfortunate you were charged "change fees", even if your travel wasn't until february...our travel to SXM was for Dec 2017, and we were able to change our destination for the same period without "change fees", but we did have to pay the difference in fares, which was like $850 for my wife and i

also, buying tix as soon as they're released (usually ~330 days out) doesn't always guarantee best fare...you just need to have a a fare in mind you're willing to pay, then go for it when you see the fare is in that ballpark...we could have saved some $s on our outbound this coming december if we had waited more, but am happy we jumped on our return when we did since that fare has increased quite a bit, and had only dropped briefly when we bought it...we actually bought our return a couple months before the outbound

but for award travel, we jump on that sh*t usually as soon as seats are released