I never received a 1099C from a Credit Card Company. I know the amount that was written off. How do I report this on my return?

A third-party collection agency was hired by the credit card company. They gave me the offer and I accepted it and paid it according to the terms given on the letter before the due date for the amount offered. No 1099C was received but the phone calls quit coming in. Who do I say the debt was written off by?  the Credit Card Company, or the Collection Agency who took my payment?