Product: Student loan

I have private loans through Sallie Mae from when I attended XXXX XXXX  in XXXX XXXX, FL from XXXX or XXXX of XXXX until XXXX of XXXX, which is when I graduated with an XXXX  Degree in XXXX XXXX XXXX 
The first problem was XXXX forcing Sallie Mae down my throat, claiming my requested loan amount couldn't be fully covered by federal loans alone, that I would have to split it between federal and private. I was living on my own in Florida and working as a XXXX  at XXXX XXXX in XXXX XXXX, FL. That job wouldn't pay people a living wage so I unfortunately had to take out more on loans than I wanted to. So, my total requested amount for the entirety of my program ended up equaling to approximately {$60000.00}, approximately {$40000.00} of which went to the actual program. This has all been a domino effect to the circumstances I am enduring to this day. 
I have been continuing to have issues with Sallie Mae practically since day one. Just because I had a cosigner, they wanted me to pay $ XXXX right at graduation. Mind you, most people aren't immediately able to get a job in the field they got a degree in right after graduation. I was only able to pay that amount for a year when I called them and told them I couldn't pay that amount anymore. They kept trying to tell me " well you have to figure out a way to make it work, '' and I told them I had been and couldn't do it anymore. I stated it multiple times just in that one phone call until they finally decided to offer an alternative. The woman didn't fully inform me of the modified payment plan I had elected, only that each loan ( I have three with them ) would increase by approximately $ XXXX after the year of modified payments was up. She didn't tell me I wouldn't be eligible for other loans or that I couldn't refinance. 
Fast-forward to a year later when my payments increase again, but not only that, interest rates have skyrocketed. My payments are now upwards of $ XXXX. I'm trying to talk to them and get help because I know I won't be able to afford payments like those, being a single income household. My cosigner is also not able to help me. Regardless, they should be making it affordable for the borrower, not the borrower and the cosigner. I try to make some payments while getting this figured out, but they're no help at all. Eventually I stop paying because I can't afford to. Meanwhile, I'm trying to refinance on my own, and with my cosigner, with other places because I know I can't refinance with Sallie Mae. Nothing is working and eventually, my account sinks further and further into debt, hurting me and my cosigner because of Sallie Mae 's ridiculous loan terms. 
Sallie Mae keeps calling and I tell them until they can work with me I can't pay them because I can't afford to. They keep going back and forth with me and trying to back me in a corner. ( They've done this to me and my cosigner frequently. ) I'm adamant and they finally concede and get me to an underwriter to help me with a repayment plan. I make a year of on-time payments of $ XXXX to get my account back on track and after that year is up I can submit an application to release my cosigner and get my loan reevaluated for my income alone. 
Everything seems to be going decent until recently. In XXXX XXXX I knew I wasn't going to be able to make my payment on the due date of the XXXX, but I knew I could pay it by the XXXX when it's considered late. I talked to a man at least three days prior to the processing of the payment, which is their cutoff, about taking off my auto payment. He told me he did it for me and I had nothing to worry about except manually put my payment in by the 14th as stated. A few days pass and I see that a partial payment came out of my account and the rest was backcharged on the XXXX. I look in my Sallie Mae app and my auto debit is still on. I turn it off and manually make the rest of the payment manually on the XXXX. 
Fast forward to XXXX I'm checking my app again to make sure the auto pay is still off and I see my payment due is going to be {$580.00}. I call and speak to a woman named XXXX. I ask where the extra {$20.00} came from and she stated it is an unpaid fee from my payment being back charged. I told her it wasn't my fault and she told me I still had to pay it. I vehemently refused to pay that money when it was not my fault, but the fault of the man I spoke to in XXXX. She kept blowing off what I was saying, but I was not taking the falling and paying {$20.00} for something that was not my fault. I told her I wanted to speak to a supervisor then to have this fee removed from my account. She still blew my off and wouldn't transfer me. I had to say multiple times that I wanted to make sure people listen to this phone call and the previous one then because I refuse to pay it ever. She finally said she could send it to the XXXX XXXX for them to review the case. She gave me a case number and told me not to expect a response for approximately a month and the fee will stay on my account until then. What happens though if I don't pay the {$20.00}? Will my account have a past due delinquency and ruin my repayment plan? I have nine payments done and three left. If I lose my repayment plan because of this, I don't know what I'll do. 
These people are impossible to work with. I wish I had been able to take my whole loan amount out through the federal government because this has been a nightmare, and I'm not the only one. Please look at the XXXX XXXX XXXX reviews. The XXXX  is a joke as well. They state reviews don't go into the grading of the company when customers make a business, and we're not happy. Sallie Mae has assisted in fraud by not helping a woman who had a random man take out a loan for his son under her name and they essentially told her " too bad, too sad. '' This has gone on long enough.