I can't pay my AT&T phone bill?

I haven't been able to pay it since March, and the phone was shut off the end of April with a due balance of over $400. They told me that i had 55 days to pay off the debt and at the time I had my job. Unexpectedly I had an family emergency and had to go to Mexico. My boss wouldn't understand my situation, so I had to quit my job so I could go. I stayed there for two months and just came home two days ago. Now my AT&T bill is over $700 and I don't have a job and am expecting a baby in the winter. Does anyone know why the bill jumped so high and what my options are? I have to take care of everything myself and right now, I have no financial support. Will they understand and work out some sort of agreement until I can find a job? Or in anyone else's experience, what has happened??