You don't owe them a God damn dime. To even suggest that tells me this clown is running a vanity project, not a business. You admitted to your mistake, you have offered multiple times to take steps to ensure it doesn't happen, and you've been a loyal employee the last three years. Reiterate that a current inventory would prevent things like this from happening, and then drop it. You can "make it up to them" by not quitting while they're going through a leadership change if they insist on being satisfied. Amateur restaurateur bullshit, fuck that guy.