Collection on Student Loan

I have a defaulted student loan amount of approximately 1500$ (about 10 years old, been through multiple agencies and treasury offsets)and GC Services on behalf of USAFUNDs is trying to collect. I called them and the rep told me its too small to qualify for rehab but under William D Ford I could make 4 monthly payments (If I qualify???) and have the negative credit lines expunged from my credit report. She stated that I would then pay the original Sallie Mae any difference left on the balance and once finished it would show payed as agreed on the credit report. I advised her I did not want to give any financial/personal info over the phone and could she send the application for the 'Hardship Process' as she called it via mail. She stated that is not something they do and unless going through a 'Phone Setup' where I give all that info, I could not receive any documents in the mail. What is my official status and what should I do at this point? My greatest concern is removing the negative credit markings as she claimed I could do. I gave them my current mailing address but she refuses to agree to mail anything first? Is this normal?