Catawiki review: Customer service and appraisals

I have exchanged, and kept, my correspondence ( such as it is) with Catawiki.
My query as to how the same expert could appraise two identical Luxury Brand Watches being auctioned at the same time, one of a non-EU source, with a difference of Eur. 1.4k--Eur.1.5k in the estimates was eventually (sic!) met by an irrelevant reply as to market conditions and the Catawiki business model.
The expert replied in a one liner to the effect these things happen!
Catawiki refused to escalate the matter to Senior Management and then arbitrarily closed the discussion!
Coincidentally, at the same time,my Paid "Orders" disappeared making it impossible to contact Sellers and "Help" immediately. My requests for their reinstatement were ignored, as were my other complaints ( a provably paid for item not being processed by Catawiki; a wrong description item that I could not contest and awarded Bonus Vouchers not being redeemed).
No satisfaction as yet--at least two weeks into first notifying the problems-- and being sent all around the pre-answered but 100% unhelpful AI responses.
I can full well believe why dealing with Catawiki should be taken with huge caution and cannot undertan, given te nature andquantit of complaints, Catawilki has not been refrred to the ompetent Consumer Authority.