How to get rid of my student debt?

There are two separate issues here. First, did you pay with student loan funds or did you pay in some other form (e.g.; a personal check)? If you took out a loan, some student loan debt can be discharged in bankruptcy, but it is a fact-specific inquiry. If you are in New York, for example, recent rulings indicate that private student loan debt is dischargeable in bankruptcy. For government student loans, you need to satisfy what's called the "undue hardship" standard - a difficult but not impossible standard which requires you to establish that requiring you to repay the student loans will cause you to live below any reasonable standard of living. If you paid by a personal check, and the institution already has the money, there's likely no way to get it back. If that's the case, you should look at their deadlines for cancelling. If you can't find them on the school's website, ask for a copy and they will provide it. See if you missed the deadline to withdraw/cancel or not. If you did, then as counsel above notes you are likely out of luck. But it's worth checking. I hope you are not out too much money - good luck!

If you dropped the class after the add/drop period, you are responsible. Perhaps there is some internal appeal procedure at the University.

If you failed to comply with the deadlines for withdrawing and you got stuck with the charges your only practical option is to pay what is owed. Most institutions have well publicize deadlines for dropping/withdrawing etc.