Error 409 when registering a second-hand Xbox console for Dev Mode in Partner Center

trying to register it for Xbox Dev Mode under my developer account in Partner (Center Partner Center Xbox Devices portal).However, when I enter the activation code generated by the Xbox Dev Mode app, I get Error 409. It seems the previous owner left the console's Hardware ID linked to their old developer account, and I no longer have any way to contact the seller.I already opened a general support ticket (Case ID: 2611100010000241), but it hasn't been routed to the right team yet. Could a Microsoft moderator or Partner Center engineer please help me clear/reset the stale Dev Mode provisioning record for this console's Hardware ID? I have photos of the console's Serial Number, Console ID, and Xbox Live Device ID ready to share via private message.Thank you in advance for your help!