It's safe to assume that the majority of people in this industry are either scammers or simply are not honest, but as wndsnb mentioned, these hash boards are so fragile, you might fix it, it works for a while and then breaks again, I have a few gears that sometimes would work with 3 boards and then out of a sudden only 1 board shows up, if I wanted to I could simply sell it as a miner that works with 3 boards but then I would be another scammer, unfortunately, this is what many people do.

I always tell my friends and clients that a video showing the full hashrate of the miner is not enough proof, I see resellers taking a 1-minute video of a miner that has been turned on for no more than 10 minutes and claiming that the miner is fully functional, it's pathetic, to say the least as many, many issues will only show up after mining for a few hours or days.

On the other hand, your supplier could very well be honest, they might have fixed the hash board and then it just broke again, to them, you could just be lying about it, or you might have overclocked the hash board beyond the max because you think you will get a refund or something, and most importantly, they probably think they did their part and deserve to get paid, if they would refund every sale the will go broke, this business is very complicated, I honestly wouldn't be running one even if I had the tools and the skills needed.

The moral of the story here is to try to send your miners to repair centers that shipping to doesn't cost you a lot, you should always assume that you will have to ship it back to them multiple times, sending the gear overseas to fix it is a huge gamble which will more likely than not end up with a negative outcome.