PRN scheduling nightmare

I've been working at this assisted living facility for about 8 months per diem.... the first few months we had a really great scheduler. i would usually email her a month ahead of time, ask her for available dates to work, and she would email them to me. then i would just send her back the ones i wanted and that was that.

fast forward to about 3 months ago.. the scheduler got a promotion and they put some new guy in her place. he is awful. he has scheduled me on days when he already has someone scheduled on numerous occasions. most times i just go home and let the other person work, no problem really, just a little irritating that i got all ready and went to work for no reason.. but today i got a voice mail from a girl at work saying im on the schedule for 5-9 today and shes wondering where i am.. i do not recall telling him i would work today, and im pretty positive i didnt because i never schedule myself for mondays because i have clinical on mondays and im too tired to go in.

so i havent called them back yet, i really dont want to go in tonight because im dead tired and its not fair that i didnt schedule myself to go in.. but i feel bad giving them more work when its not their fault either. i dont want to get fired, but i dont necessarily want to stay there either.. ive been looking for work elsewhere but no one has called me back yet.

anyone had crap schedulers like this? what would you do? just wanted to vent a little i guess.