I need help completing a Short Sale

I am trying to get approval for the shortsale purchase of my home. The sellers agreed to our price after doing everything Chase required (marketing for period of time...)The approval by seller was on April 25th. They submitted the paperwork immediately. 3 weeks later they were told (finally) that the application paperwork was in the wrong pile and would be transferred for short sale. Our price is reasonable based on comps. We sold our house and are now renting the short sale property. We locked in to 4 7/8 rate in May, w understanding that we would have to rent the house from the sellers until the short sale paperwork was processed. Rate lock is only until July 7th. We have approval for the purchase, have paid $ for inspection, appraisal and lock plus moving expenses in here. The sellers are getting the run-around with Chase saying they need the SAME paperwork faxed in over and over again.If they don't process by the 7th closing, our interest rate will go up and we will have to move out of this house and Chase will have to foreclose with the sellers. My 5year old is registered and starting kindergarten based on the agreement to sell by the seller a/o the end of April. It is bleeding money from our family. We want to close, have the money, and yet Chase would rather go into foreclosure than have a good family who is already living at the house buy it for fair market value. What can we do to expedite this with Chase in the next 9 days for closing? PLEASE ADVISE AS WE ARE DESPARATE!