Since they're no longer under warranty (falling voided that), stop shaking it while the music is playing unless you want to kill your amplifier.
With the amplifier turned off:
If you can see the screws that hold the woofer in place, remove them and carefully lift the woofer out. It's likely that the heaviest component on the crossover has come loose- re-secure it. They may have used hot glue- if you have that, use it.
Since you didn't mention any kind of scraping sound, I think the woofer and tweeter are OK. Once the crossover has been repaired, you should be OK.