Can I be charged with Theft or fraud? or will they sue me for the money owed?

My friend had some items on Ebay for sale...Well later decided to not sell them...It was too late to cancel the bids and the buyer refused to cancel the transaction...Well I never shipped the items so Ebay refunded the money to the buyer but they want me to pay them back. I don;t have the money to pay them back right now...Will they just sue me for what's owed?