If you do have to give back the horn, take up the tuba instead - take the advice of Flanders and Swann.....

Seriously, hope everything works out for you, I've been in similar situations, you bust your arse to do things for people and they crap all over you, then blame you for the smell. They ain't worth killing yourself over. Mind you, if you aren't the only one at the fund raiser, but are the only one threatened with having to pay, you could get justifiably angry.... I would....

Take care, and keep making those puddles....!

LTS