With the game being “fairly new” don’t they come with a warranty? I have never purchased a NIB so I have no idea what the warranty is, but would think with only 300 games it can’t be but a few months old.
I have never worked on any of these new machines (anything made in the 2000’s) so I am curious what the issue is. Flippers are usually a really straight forward component to deal with.
Hope you solve it soon. Hang in there, great community here to help.