Student loan crisis, still owes ~$88,000 after 20 years of paying.

Student loan crisis-My daughter Graduated in 2011 and been paying her for portion, I just paid off my portion last year. I was trying to help her out before the rule change in paying back student loans. She showed me she still owes $69 K on principle and $18 k in outstanding interest. I think something has been mixed up with all the loan consolidations because I have already paid ~50K over the last 20 years myself. I have seen institutions that can do an audit on student loan history, would you recommend something like that or do you know a better way to handle this huge dept.
She is currently married and employed with a good salary and paying ~$500 / month towards the loans, I am retired (pretty financially secure) but not able to fix this problem. I have most of the original Nelnet loan numbers, which have been bought and sold several times to multiple private loan companies, currently all with Mohela. I enjoy your show on WGN radio and the one thing I learned was to Pay off all debts before I retired which I heard several times from your show. We would appreciate any suggestions you may have.