I recently picked up my 92 400E from a local body shop that had done some insurance repairs. The car's front end was totally smashed. The following parts where repalced:

Radiator, AC condensor, Aux fans, too may lines and hoses to mention, belts, water pump, ect... you get the idea.

I picked up the car last Friday, first thing I noticed was that the steering was really slugish and heavy and the car was making a tapping and grinding noise. Without ever drivivng out of the shop I checked the power steering resevoir and found that it was empty! I asked the shop what the deal was? The shop added some fluid and said it was no big deal they must have forgot to fill it. Ok so off I went. After a few miles my engine started to over heat.
I said enough is enough so I puled it over and had it towed to an authorized repair shop to have the car checked out thoroghly. The shop found that the replacement radiator was defective, and I had a leaking power steering pump. The insurance company's damage accessor was called to check the car out. Now the accessor claims the leaking power steering pump is not a result of the accident. I did not have a problem before the accident with the power steering pump, but now it leaks so badly that all the fluid leaks out , so something happened to cause this? How can I proove that this was caused by the front end damage when there is no visible damage to the pump that the accessor can see?