Music instrument help needed, urgent?

I play an instrument. I have private lessons, but I also play in a band, and the band provides my instrument. I would like to carry on practising the instrument, but to do that I need to stay in the band, and to do that, I need to re-audition, meanwhile, I missed the audition because of another committment, and even if they reschedule it, im not sure how well id do, because i have no piece to play, and no exercise sheet, as the music service distributes them, and i have private lessons. My parents have said that buying a new instrument wouldn't be good right now. I don't want to quit. I haven't told my parents anything yet. Please, please help!!!!!!! What should I do?