Firestone Complete Auto Care Drove in for 2 tires, towed away with blown motor Wilmington, Delaware

On 10/8 I visited the location on Old Capital Trail in Wilmington, DE to have 2 new tires put on my 1997 Plymouth Voyager, requesting that the 2 tires currently on the front be rotated to the back(the right rear had blown out) and the 2 new tires be put on the front.  I made an appointment for 4:15pm and after 2 hours the technician (Sean) came out with my keys.  Upon getting to my vehicle, I saw that the spare tire was still on the right rear and the flat tire was still in the trunk.  Sean said I could wait or come back in the morning.  Since my wife works at Sears right next door, I said she would drop the van in the morning. 
 
The following morning (10/9) my wife dropped the vehicle and took the key into Sean.  At approximately 1pm, Sean called to tell me that the tires were done.  He then asked if the vehicle had been stalling on me (it hadnt).  When I told him no, he said he would look into it and call me back.  At 3pm, Sean called and informed me that the motor was blown, I had no compression in 3 cylinders and oil in the intake.  When I asked how that could be, he said Sometimes a motor will just jump timing causing that to happen.  He said I had 3 options, Firestone could make the repair, Firestone would refund the money for my tires and pay for a tow anywhere or I could leave the van and Firestones restitution are would be in touch.  I found none of those to be acceptable, since I dropped off a vehicle that had been running perfectly for nothing more than tires, and now had a non working vehicle.  I called Firestone Consumer Affairs and filed a claim and paid AAA to tow the vehicle to my mechanic, since there have been numerous vehicle break in issues in the area around Firestone.
 
On 10/10 I received a call from Jessi in Claims who took my report and said an inspector would go to my mechanic (Everest Auto) and look at the vehicle on Thursday, send her the report and I would have an answer on Friday.  I notified Everest so they would not touch the van until the inspector looked at it.  The inspector didnt show until Friday and my numerous phone calls to Jessi for a status update went unreturned until this morning (10/15).  In addition, on 10/10 I received a call from Eddie Vega, the Assistant District manager requesting a callback to tell him what happened.  I left Mr. Vega a voicemail with a brief description and asked him to call me back, which still has not occurred.
 
I received a return phone call this morning (10/15) from Jessi stating that she reviewed the inspectors report with management and that based on the inspectors report, they could not see any correlation between the tires being put on and the blown motor, and would not be covering any of the repairs associated with motor failure. I have asked my mechanic (who is looking at the engine) to provide a report on what the failure was.
 
The facts are clear for me that a working vehicle with NO mechanical failure issues was dropped off for new tires and that the motor failed while in Firestones care.  The excuses provided to me for why it occurred do not add up.  A motor does not go from running fine to being completely dead like that.  Had there been oil in the intake or no compression in the cylinders the vehicle would have been barely drivable and would have been smoking and backfiring.  This was not the case.  I feel Firestone should pay for the cost to repair or replace the motor at a repair shop of my choosing and nothing less than that will be sufficient.