I purchased items from Circuit City in 2005. I was contacted almost 2 years ago regarding the debt I owed. I have been paying $100 per month. The kicker is that they want me to pay $1300. On top of the debt. Three questions: Circuit City is out of business. Does this remain as a valid debt? Is there a limit as to what they can charge me above the amount of the debt

It is a debt you owe. The $1300 may be late fees when was the last time you made a payment? Just because circuit city went out of business does not mean you don't owe. A finance company is the one that held the circuit
City credit card. Not circiut city the store. As the amount they can charge look at the fine print of what you signed