I don't want to defend anybody's wrongdoings, but since you're talking about Thai/Westerners - at the end of the day the Westerners are dealing with Thais, Thai mechanics, Thai "partners", properties in Thai wives names, and last not least Thai law and Thai police (which is not the same thing) - so what's a Westerner to do?
I met Peter only once and had the feeling he's a straight guy, but doing biz in TH can be very tricky, lots of aspects are out of your control, really. I bet he was busting his butt to make an honest living, but you're swimming against a strong torrent here, if you know what I mean.
I've had problems with a local shop because they bought a bike I explicitly told them NOT to buy using my deposit; of course they did. I helped them, sold it over the internet, a farang bought it sight unseen, it was technically okay, I put some decent mirrors and better tires on. I didn't make one baht, I sold it for the same price they bought it for and kept the money. But then the shop couldn't produce the invoice - a thai partner ran off with titles, invoices and cash, apparently. So now this guy called me and I had to tell him after he paid that there is no invoice. That made me look like a crook - because I was dealing with Thais.
I've been talking bad about the shop ever since and don't trust anybody anymore. But I stop by on a regular basis and demand my money back. There were still 40K of my deposit due. They told me to wait, they're almost broke. I did wait for half a year. When I saw a few newer bikes sitting in front of the shop, I asked them how things are, and they said they would pay me 5K every week. Well, they tried hard and paid about 5K a month, now there's only 10K due.
I think Thais are not bad people, they just got a knack for getting into trouble. A partner rips them off, a mechanic sells privately on the side, the boyfriend of the sister breaks in at night, or the place burns down, the lease ends and they're out in the street - there's no end to it, I've heard so many stories, my favorite is that "lightning struck" and the employees were afraid to go to work. Plus a few ghost stories...
Main thing is to stay relaxed, complaining doesn't help any, just hope for the best. After all, it's only money!