2003 Other Subaru Models All Wheel Drive Automatic 115000 miles

Our car is a Subaru Legacy Outback Wagon LL Bean Edition. It was in good condition until a man backed into our front end causing serious damage to our vehicle. So far, 4500 in repairs, 3 visits to the repair shop, including air conditioner and heater condenser fan and shroud, steering gear and linkage pump and hoses, udder pully, bumper, grille, fender, fender cover, radiator panel, underbelly cover, and list goes on... I think that the repair shop is just fixing enough to get by each time and we have to identify the problems! We noticed a slow oil leak. Car never leaked before accident. Mechanic said due to 1" crease at drain on oil pan. He said it was accident related. The other party's insurance company is saying that there is no way it was accident related. I think that the impact from the accident and subsequent compression caused it. What do you think? Can't it be accident related?