I missed student loan payments, and forbearance was added retroactively - is there anyway to fix my credit history?

I have been going to school on and off, and switched colleges several times. Somehow in the disarray, my contact information with nelnet who is servicing my student loans was never updated. I know this is ultimately my responsibility. However, I wasn't notified when my student loans went into collection. Again, I understand that is ultimately my responsibility. I only found out about this when I ran my credit report to see that my score dropped from around 750 to a 560.

I asked if they would be willing to write letters to credit reporting agencies to help explain the situation, and they said that they would only report if I was school or the military. They said it is against the Department of Education policy.

Does anyone have any advice that could help me remedy the situation? Thanks!