Two different things . . . Forgiven debt and charged off debt.
Charge offs do not affect your tax return and you will not receive any notification from the debtor that you bill is being charged off. In addition, you still owe the money.
Forgiven debt is usually the result of a negotiated settlement with the debtor. You owe $7000, pay $3000 and $4000 is forgiven? You don’t owe any more money and you will receive a 1099-C ("C"ancelled debt) to report the forgiven debt as income on your taxes.
BOTH will show up on your credit report and both will be questioned during your investigation.