Our Mercedes mechanic while replacing air matic block valve assembly noticed that airmatic compressor filter was installed in reverse direction resulting dusty air not being able to filtered out. As a result internal component may have damaged. Still give malfunction codes. He thinks the air filter was installed wrong in the factory by Mercedes.

I brought the car to Mercedes dealership for further investigation explaining them what I was told by other Mercedes mechanic. Car is still in the shop.

What are my chance to have Mercedes bear the cost of repair when the part was installed wrong by them?

How do I contact Mercedes to file complaints?