A new Tone Hammer 500 costs $670. Let's run the scenarios...
You just need to consider the options and figure out which one is most worth it to you. Good luck with it.
- You forgive the BL and eat the cost of a new amp. You keep the band relationship intact, which we assume represents some future gig income for you.
- You forgive the BL and ask for voluntary help with a new amp. Might be a sticky conversation, but you keep it cool and gratefully take whatever they can give you out of good will. Band stays intact.
- You tell the BL straight up that he caused your damages and owes you a new amp. Unless the BL agrees, you probably burn the bridge and end up eating the cost yourself, unless...
- You give the BL a chance to make it right, and if he doesn't, you file a small claim action. You would probably want a witness to confirm your side of the story, which you may or may not get if you just burned bridges with the band. Consider your filing costs too, as well as the grief and the time.
You just need to consider the options and figure out which one is most worth it to you. Good luck with it.

No offense ... not trying to make 'the list'