ASIN removed due to authenticity complaint

Hello, I why so ever got a complaint about a pricey smartphone. The total stock was 2, 1 got sold, the other one is now inactive.

Both items where bought on a different European Amazon marketplace. I have provided the invoice, name and address of the seller several times.

Amazon still wants more “detailed” information but does not mention what exactly is missing. Does anybody know how to resolve this?