It’s not good that you signed before the move was completed BUT it’s great that you have the pics of your property loaded and undamaged then damaged at the final destination.
Get a written estimate from a reputable restoration person here on pinside ASAP. Make sure it’s on their letterhead with your full name and address and that it specifically states repair funhouse pinball machine cabinet damaged by tri star moving on whatever the date it was they moved it. Print the pics of it loaded and damaged at final destination. Email a letter to the moving company stating that their movers damaged you property and specifically state that you are filing a damage claim. Don’t reference any of their pass the blame game BS. Simply state the facts. Make sure you attach the before and after pics to the email. You should also send a copy of whatever you email them registered mail so they can’t deny receiving your email. If you talk to an attorney cc (not blind CC)him on the email. You want the moving company to see what your sending them is also being copied to a lawyer, that way they will know you aren’t screwing around.
Good luck and keep us posted!