Short sale is not the same as foreclosure. If you were permitted to do a short sale, you had to get approval from both lenders (or the same lender if they did both the first and second). The papers approving the short sale should have specified if you would owe the balance.
So unless your papers specified that you would not owe the difference, then you would be liable for it.
Has the property been sold? Once the sale goes through, then the balance owed becomes like any other unsecured debt, meaning that it can be negotiated.
Your best bet is to speak to a real estate attorney specializing in foreclosure defense as they would most likely be familiar with these issues.
