Have a payment plan but i am not able to pay anymore,husband out of work.what can i do?

First figure out why you are in such a bad financial condition.
Set up a budget to at least keep from getting any further behind with other bills, And make sure you do not get any additional debts.

Do you own a home , are you working, is there a judgement against you already.
If you can not do the plan you agreed to, ( was it in writting)

But at the end of the day, if you do not have any money to pay them, you don't have the money.