Let me correct some misinformation from my last email. The PSLF (Public Service Loan Forgiveness) program is the 10 year forgiveness part of the IBR that requires you work in a qualified hospital. The 25 year forgiveness is for everyone in the plan. Interest that builds on your subsidized loans that is above the amount of your monthly payment is paid by the government (possibly the company in privately offered Staffords) for the first 3 years in the program. So if your monthly payment is $0, the government is paying all your interest on subsidized loans for 3 years.
Anyway, the official FAQs website for the IBR is:
studentaid.ed.gov/students/attac
... _FINAL.pdf
Again, much easier to read this than call the department of education and try to get them to help you, unless they route you to Mohela.