Im not sure what reality you live in, but for me as the seller:
claiming something doesnt work after having it in your possession for almost 3 weeks after receiving it, is a RED FLAG.
Opening up a claim without even messaging the seller before hand, RED FLAG.
Posting up your BEST 10900K a day after receiving mine, RED FLAG.
SELLING off your 'BEST 10900K' before testing out a new one, RED FLAG.
Per your for sale post, you still had a working, or as you refer to it, 'YOUR BEST 10900k' in your possession until you sold it on the 18th of October. That is 10 days, which you could have easily installed that KNOWN WORKING CPU into the 'suspect' motherboard, and tested it to know IMMEDIATELY, if there was an issue or not. RED FLAG.
I sent you the picture of the CPU from the BEGINING with the label and I EXPLAINED to you that I BIN for 24/7 daily stable, NOT XOC. You asked me for additional screen shots and I provided them and the DATALOGs to go with the str ess testing I did for the CPU.
I'm not sure who you are trying to fool, but it aint working. I've uploaded all the chat logs, and pictures. anyone thats bored can look thru it an see that your story doesn't add up. No one offers to buy a CPU for $1000, from across the Atlantic, and sits on it for weeks, and then randomly does a claim with out saying a word to the seller beforehand.
Congratulations, you played yourself.