When ripped off in a car purchase a reckless guy seeks revenge, but must defend himself, his best friend and an attractive receptionist against a psychopathic car salesman.

Here is attempt number 2 (putting inciting incident first):

When scammed in a car purchase a reserved accountant seeks justice and inadvertently aggravates a psychotic car salesman.

Thanks for the feedback so far. Below is my much thought-out new attempt.

You are right, Mr Literal about his flaw. I originally gave him the wrong one. And Nir, I tried hard to put the inciting incident 1st but was hard to make it sound good.

Any extra feedback would be awesome:

When a reserved accountant seeks justice over a car rip off he inadvertently aggravates the psychotic car salesman.

Read up on logline conventions they exist for good reason, here is a helpful guide on this website:
https://loglines.org/howto/