Here we go again. I had a similar experience with Amedia-Computer - France several years ago. My advice would be to start a transaction dispute with your bank as soon as possible.
I waited too long, believing all of the delay tactics. Now I am stuck with a poorly designed $3500.00 piece of trash that cannot be depended upon. It took me almost 2 years of humiliating pleading and groveling to the entire Amiga community to even get that much. At one point I even offered my V4SA as a reward to anybody that could help get my motherboard returned to me.
By now all the X5040 boards must be almost 10 years old. The latest software update killed mine, now it won't boot from anything. It still makes me uneasy to look at it, so it's packed up for now. After 40 years of great experiences enjoying, using, and upgrading my collection of classic machines, I never dreamed that I would get screwed so hard buying the supposed "best" Amiga available.
Having been through this before, I feel your pain. It takes guts to admit that you have been ripped off for $3700.00 in a public forum.