Looking to cancel interest as debt has been paid,NYC

Hey everyone, any and all help is appreciated to understand any tools I can find, after 10 years I have paid the original amount of $63k loan. Navient still wants $79k of my blood. I am striking to learn options as this criminal rate is 100% unacceptable debt on my record I need to eliminate to live life. It was a Smart option loan from Navient, that has gone from 2.3% to 14% interest rate currently super high interest. Any tools that exist to fight this in court, current resident in NYC.