Product: Student loan

My issue is relatively simple. However, getting it fixed has been a matter of bouncing back and forth between my school and my lender for YEARS. 
Back in XX/XX/XXXX, it shows on my credit report that I have late payments regarding my THEN XXXX student loan. The problem is, I was still a student and should have been under deferment but here is what happened. 
Due to some accouningt errors at XXXX University, XXXX showed that I had a balance of more than {$5000.00} that had to be paid back to them in order to get back in school. The whole ordeal lasted 1 year. For the first 3 months, NO ONE knew WHY I owed the balance. I had moved out of state which complicated getting things fixed. I kept getting promises for call backs that never happened. Eventually, XXXX ( spelling may be off ) at XXXX University began helping me with my situation. However, he too kept asking me to give him time to review the situation, something that took an additional several months. He would ask for a few weeks to look over things and when I would followup, he would tell me " Ohhhh .... I have a meeting about this next week, give me a few more weeks to review this ... '' and that went on for a several months so at this point we are at about 6-7 months of me being out of school. 
Now, when you first get a student loan, you have a 6 month grace period before your loans begin needing to be repaid. Here is where things get interesting. 
When I originally signed up for classes at XXXX, I provided them ( XXXX ) contact information for me such as my personal email address and phone number. That was back in XX/XX/XXXX. The school offered it 's own email address to students but the username and passwording format was always very difficult for me to remember so from DAY ONE that it was given to me, I could never remember the actual email address OR how to access it and never cared to because if we ever needed to use email, we would contact our professors directly using our own personal emails. ( that is important for a reason coming up ). 
So during this extended time of me NOT being in school, my 6 month grace period ( unbeknown to me ) had expired. Sometime in XX/XX/XXXX, while my mother was XXXX, I had to take off on a 3 month medical leave of absence and when I came back, I had to redo my financial aid paperwork. This time, the FAO at my school was the one to fill out my XXXX paperwork. NOT ME! And when she did ( her name is XXXX btw ) she gave them my school email. ( Through my own investigation, I found this out much later ) So during this 6 month period where they were stalling and keeping me out of school, they were also reporting to XXXX that I was not enrolled as a student. The truth is they barred me. 
Around this time either XXXX or XXXX etc, was offering a free 1 month membership to students but you had to use your schools XXXX email to register so, I contact IT to get help accessing my email account to do this and noticed that I had been getting email after Email from XXXX telling me they were trying to contact me about a loan. By this time it had been 8 or 9 months of me being out of school. So, they had been trying to contact me about my student loan after my grace period and NOW I was showing as having been Late on payments that would have started after that 6 months. I called them ( XXXX ) to find out how they had gotten that email and asked them how they were contacting me. They specifically admitted they did n't make any calls but contacted me through email only. This may be because they were transitioning from XXXX to the Dept of Education and now Navient around the time. I do n't know. But I have XXXX negative reports to my credit agencies showing I have Late payments for XX/XX/XXXX. Neither company can help me. I disputed with Credit agencies several times with no luck! PLEASE HELP.