While finding an Agnus I bought an FTDI RS232 USB adapter to read the DiagROM startup log. Looks all ok, but I want to share here just for knowledge.

Seriously, these types of business practices can't be tolerated. Once communication fails, I no longer accept any delaying tricks or tactics before beginning the transaction dispute process with the finance company. I use a credit card or similar now, especially for overseas transactions in different currencies, and just pay within 30 days to avoid finance charges. For large purchases, there is also third-party escrow. The lesson was hard learned, but it has saved me money several times on difficult transactions since then.

I hope you end up getting your money back, but I feel that it may be too late by now. Honestly, I feel sorry for you if you do receive the X5000-5040. My 5040 complete system has been one of the worst, most expensive, and frustrating mistakes that I have made in the last 40 years on anything!

In my opinion, mine and others 5040 motherboards are somehow flawed at a firmware/hardware level and have never/can never work properly. Somehow, this behavior seems to have quietly been acknowledged and accepted as Standard Operating Procedure. I guess some people are happy if they even startup at all - so just deal with these nagging issues that can't be fixed.  This is my guess as to why new 5040 motherboards don't exist and likely won't be made again.

It almost feels like the 5040 motherboard and or firmware wasn't quite finished, and they pushed it out too early anyway. My 5020 on the other hand is a rock-solid pleasure to use. I had serial debug setup on the 5040 and even bought the device to read the MCU debug output. I gave up when the last update trashed the boot drive. Now, it doesn't boot from anything.

AmiBench is only available on A600GS and A1200NG based Amiga emulators, it won't run on actual Amigas I'm afraid.

I 've met Amedia people personally and to me, they seemed honest persons. I am surprised about what you are sharing here.
But if you asked for them to return your payment, they should definitely do so.
I hope this will be solved soon.

Sad to hear. But not unsurprising. The launch of the X5000/40 model had no fanfare whatsoever, and yet it is supposed to be desirable?! The A600GS/A1200NG have better browser features!