I've had to deal with one just like this this week.
Main dealer, and this absolute twat has given them, and now me, loads.
I was so so close to losing my rag with him, whinging and whining about the tiniest marks imaginable in his interior.
I reminded him that his Corsa was in fact 3 years old, and suggested that if he wanted something in near perfect condition, that he bought new.
He was complaining about a miniscule scorch mark on the carpet...amongst other things...but it was so small I couldn't actually see it!
The horrible little chavy white baseball capped scrote only grabbed my hand to guide it to said mark.
I shook him off and reminded him not to touch me, and simply walked away to get the gaffer to sort him out.