I agree, this is a crappy and unfair situation.
Unfortunately, there is little you can do.
They will claim that these points are "promotional" and hold no real value.
I reject that claim, because these so-called "promotional" points are a big part of the reason people are playing there. It could easily be argued that many grinders would not have played on that site if the loyalty points were not sufficient.
Pokerstars did something similar when the DOJ shut them down on Black Friday. You were forced to cash out your FPPs in "blocks", robbing you of value. You also had a remainder of points at the end, which became worthless, again robbing you of value. And finally, your points were cashed at the rate according to your current VIP status, which was ridiculous, because it rewarded active players at the time and screwed players (like me) who had taken a short break from the site. I was Supernova when I earned those points, so I should get to spend them at Supernova rates if I can no longer play to earn Supernova back.
Anyway, Pokerstars didn't give a shit, and idiots lauded them for being "generous" to cash out these points, not realizing that these points represented real value that they earned -- equivalent to rakeback. They weren't a gift.
Back to your situation...
I understand all of your issues. There isn't time to clear bonuses. The notice given was too short. And given the lack of time to clear bonuses, you are stuck instead buying overpriced merchandise in the store as the only viable option, thus KILLING the value of the rakeback you thought you were getting.
It's a big screw job, but I don't see them changing anything.
Shame on bwin.party for this.