NJ Class Loan Gone to collections

At the beginning of the year I received a letter from a collection's agency stating that they were now in control of my NJ Class loan and I owed them $26k immediately. I am currently unemployed and have been since graduation and have no means to pay any of this back at all. My mother was a co-signer but she has been out on permanent disability for years and has a much lower income then when we filed for the loans. I contacted the agency and they said that I would need to pay the back interest asap which is about $1k and its been 2 months so higher now. And then Id have to at least pay the interest each month which is $120 and some of the principal on top. I have no way to make any of these payments at all. I am not sure what I can do about it or what the agency can do to me about it.