Can I legally get charged $900 in fees on 2500 perkins student loan?

My loan went to a collection agency by mistake because my deferment requests did not go though and the balance went from 2500 to 3400, then I brought it current right away be sending the loan holder an enrollment history, but is this legal that a collection agency can charge 900 to collect a loan that they made no attempt to even collect. When i asked for a copy of my loan agreement, the guy at the collection agency told me this was priviledge information and I could not see it. Does this sound fishy?