How to make a music teacher re-consider

• Don't provide materials (I have no instruments...just "First Steps in Music for Preschool and Beyond" 150 Folksongs and 150 Rounds books)
• Don't provide a place to work (I share an office, which is actually a closet with a water-test valve and I don't even have a key to it)
• Don't tell them anything (I found out they changed the date to my concert from a 2nd grader)
• Don't give any feedback until between the dress-rehearsal and the concert, and then tell them everything they need to change in the few hours before the show

I'm dreading my vacation ending.