Raptor is a small company and one guy is fronting most of the support load so keep trying, he's not out to screw any customers or provide an inferior product.
Can he actually manage returns? His suppliers should be eating the cost of faulty boards, and the article makes me think they aren't. Continued problems customer side should result in a replacement.
In the US you have full rights to a return to the person who took your money for 30-90 days (depends on state). Requests that you use the warranty or contact the manufacturer are unenforceable. Considering this, it is unwise to wait for longer than that period before requesting your money back. The federal statute of limitations for being sold a defective product is 4 years, but that is a lot harder to enforce.
Remember the AMD Ryzen returns? Why wait 2-3 months for a replacement? Demand your money back from Newegg and buy another, they have to process the refund. Also -- most FFLs either state gun returns are outright illegal (a lie) or only accepted for 3 days (against state law) with a steep restocking fee (also against state law). This is the worst case I know of.
But Radio Silence for a few months... surely that is a bit too much?
On the other hand I didn't know Raptor was this small.
However, I think people that do not see what we see in the support system are greatly underestimating the volume of Email an OEM/ODM receives on a daily basis, which then must be filtered and sorted through to determine the valid issues from the flood of spam and general inquiries. It's not something we have a solution for yet.
May I recommend a more customer-friendly way of doing this? Allow the customer to exchange their iffy hardware first, then do the investigations on your time, with the hardware in your labs.
A family friend will help me troubleshoot my electronics. So, I have seen the other side of this: I get something which is completely nonfunctional and send it back to the manufacturer who claims it is functional, and tries to bill me for the shipping both ways. That's why if I can not get a working replacement in 2wk or so I just send it back for refund.
For a real example: Are you using very well made power supplies? Maybe your board's power filtering could be better, and customers notice because they buy the cheapest supply that meets their power requirements.
In general we can diagnose and repair or replace the systems rapidly. This one case was an extreme outlier, and in the future we will just be authorizing RMA and replacement / repair.
The trick is to get your board manufacturer to eat the return cost. If you can buy testing, do so; usually it comes with some assurance that the boards work, and they either make new stock or remanufacture what you send back. If you can point to a comprehensive testing instructions that the customer would have performed it should not matter if you receive the board and it works for you, for some reason it did not work for the customer.