THE EXACT SAME THING HAS JUST HAPPENED TO ME!!

I rented a car in Switzerland from Sixt a few weeks ago. Car hire was for 3 days and without any incident. When I returned the car to the Lausanne office, there was one girl working at the desk, I informed her that the car was returned perfectly and with a full tank of fuel.

Today I received a letter identical to that of the original poster! ..
Dear client.. we have noted the following new damage on your rental vehicle ... Aluminium rim rear passenger side scratch > 10 cm deep (down to primer) ...

I DEFINITELY DID NOT DO THIS OR ANY DAMAGE! I am so meticulous with car hire, particularly damage of this size, this is something I would NEVER miss in a condition report.

What do I do?? The letter got sent to my home back in Australia, they were asking for a response by yesterday, my family only got it yesterday and emailed it to me right away.