Once you receive a 1099 C is it too late to contact the bank and ask them not to file as less than full payment received?

I notice that your not saying you feel it was an error and you actually didn't pay less than you fully owed, just you don't want them to report it as such. They have no option on reporting this cancellation of debt to you. They must. It is a requirement of the Fed tax laws just like all the other tax reporting obligations a bank, employer or just about any business must do. This is one they wouldn't have had to do normally, but you just made it harder for them by the not paying. Yes, it is absolutely income to you and absolutely known as income to you by the IRS. They cannot change the accurate reporting, as they are reporting on last year (that is prior Jan - Dec) dealings. That is, things that already happened. However, if you do pay the amount that was/is now due, they should be able to provide you with support so you can effectively reverse the income you reported and substantiate it. *It is never too late to call for more information. If the bank recognizes an error, it will file an amended 1099.