Most of the time, a debt that is forgive or canceled is treated as taxable income, because you got money that you didn't pay tax on (the loan), and now you get to keep it without paying it back, so it counts as taxable income (even if the actual money from the loan was spent long ago).
The lender issues a 1099-C for canceled debt, they should have mailed it to you, and you must report it on your tax return.
Certain debts are not taxable, but they must still be reported, and the exceptions noted on your return.
We would need to know more about this debt to suggest what to do next.
