Sallie mae collection practices not allowing people to make payments when they are offering

I co-signed for my daughter to get a student loan from SALLIE MAE, and along with a lot of americans she lost her job and she got behind on payments, so i set up payments myself as her father and co-signor on jan 2010 i put money in a account from jan, 2010 until june of 2010 and for some reason SALLIE MAE stopped taking the payments out as we agreed, so now SALLIE MAE HAS turned it over to a collection agency called national enterprise and they are telling me if i don't pay in full they cannot help me and i'm not refusing to pay and now they have added un godly interest we the people along with other students or co-signors need these unfair practices to stop.