Sharief, so sorry to hear of your troubles.
You have done nothing wrong in pressure washing the exterior of your Panda. I've done it with mine for nearly 3 years with no bother at all. Don't even mention it when you finally get to the dealers to get the car fixed.
I just hope that the car is fixed satisfactorily and that God then grants you years of trouble-free Panda motoring as he has to me.