Viking your hole gets deeper by the day.
All you had to do was play nice...
This comment by you says it all. I was in manufacturing my whole career including shipping heavy, custom, high dollar speakers all over the world. The way to have handled this would have been the following:
First off, don’t get yourself into a position like this. If you are shipping delicate, high dollar speakers make custom wood crates for them. My God man, get a freaking grip, I never once shipped speakers in cardboard boxes.
Secondly, immediately on seeing your unhappy customer’s posts contact him and ask him what YOU need to do to make it right. Yes, even if you don’t make a cent on the deal in the end.
Then sit back and watch a once unhappy customer post how well you handled the situation, how happy they are with your products and how they highly recommend your company.
Business 101 for a company like yours in an industry like this.