need more info to answer, is this a short sale where Chase is the lender, or is the property owned by Chase? you said you signed papers, were these offer agreements? If its a short sale, which I'm guessing it is, there would need to be more info but I can tell you, there's no guarantees in short sales that the terms will stay the same. This should have been explained to you when you signed. Look at your paperwork, and if its a short sale you should have signed a couple of additional documents, a short sale addendum and a short sale summary. Both documents explain the process, which states clearly that the bank will review the terms and obtain all the creditor approvals. At any time, they can revise the terms if not acceptable. That's why the terms of the short sale are not fully determined until the seller receives the actual "short sale approval" from their lender, and until then, all is open to change. again, this is a complicated process so without more info, I'm making some assumptions. But if what I've said fits your scenario, then this is extremely common and why people need to understand going in, that there are NO guarantees and the process on a short sale is very different than a standard sale transaction.
best to you