Product: Student loan

I have been paying on my student loans for over 17 years now and there are several discrepancies I have tried to resolve with the loan company, but with no resolution. 

To begin with, the loan was originated in XX/XX/XXXX, with original terms of 240 months repayment ( I wanted 180 months as indicated by my initials on the consolidation note ). At the bottom of the note, the loan official signing the document wrote in terms of 360 months when it is clear the original terms were less than this. The loan balance at the time of the note was {$81000.00} In my last communication with Navient, who now services the loan ( XXXX XXXX was the servicing company prior ), they provided a statement again showing the 360 month term ( which I DID NOT agree to ), saying I have paid 141 months of the note at {$750.00} and 219 months remain. They then go on to say that I have used 43 months of deferment/forebearance during this time WHICH IS SIMPLY NOT TRUE. I have used the forbearance option for a month or two hear and there, but absolutely have not deferred the loan for any substantial length of time since I have begun repaying the loan. I have also been repaying the loan with extra money each month for quite some time now totaling {$800.00} a month. Navient also stated that the loan would be paid off in XX/XX/XXXX. Now they have added 4 years on to a note of 360 months that I still did not agree to and is in direct conflict with what is written on the consolidation agreement. 

Over the years I have had these student loans, the servicing company has changed a few times, thus making it difficult to trace payment histories back to the very beginning of the loan. XXXX was the first servicing company followed by XXXX XXXX and now Navient. I have printed copies of much of the payment history and a personal ledger that I have kept since XX/XX/XXXX, showing payment histories and discrepancies between what I have paid and what they are saying I have paid. 

In addition to these issues, there is major concern for the balance of the loan as of today as compared to when it first began in XX/XX/XXXX. As of the day of this letter being written, the loan balance is {$80000.00}. This is {$1700.00} less than the original balance of the loan at the time of consolidation. Where has my money been going for the past 17 years, especially considering I have paid extra for quite some time? I have loan amortization programs available to me showing the balance should be SIGNIFICANTLY LESS than the amount they are showing, if not paid in full by this time, considering the extra funds I have paid each month and the incorrect terms of the original note. There are also two disbursements on the account history provided by Navient in XX/XX/XXXX and XX/XX/XXXX of {$4700.00} and {$3000.00}, respectively. I finished XXXX school in XX/XX/XXXX, so why would there be any additional disbursements? 

As you can see, there are NUMEROUS discrepancies in the manner with which these loans have been " serviced '' over the years. I ask for your help in getting these issues resolved as quickly as possible and an explanation provided as to where my money has been used other than paying down my loan.