What would you do?

I haven't worked much this year. I was filling out a bunch of applications and put open avaibility for both, because I did. Well I got two jobs, one at Wal-Mart and the other at Jo-ann Fabrics. I really like the one at Jo-ann's but it doesn't pay as much as the one at Wal-Mart. I changed my availability at Jo-ann's to 4 to 10 any day of the week and they were fine with that. So I went to Wal-Mart, which is a twenty four hour one, I am trying to change my availibilty to 11 p.m. to 3 p.m. all week, I mean that's 16 hours in the day. They wouldn't make me work 16 hours, I was just letting them know. Now Wal-Mart is giving me a hard time. WM posts their schedules 3 weeks in advance, so I can't say like my other job needs me these days, so I can work these other days or these other hours. I really can't afford to quit either job cause I am so far in debt it's scary. I mean I don't know what to do, what should I do?