Quick update on this one: the account is still deactivated, still don't know the reason (it was deactivated immediately after I tried to upgrade from the Individual to the Professional plan).

I was asked to prove my company data (which were fine under the Individual plan and to receive Amazon invoices for fees, including after deactivation) by providing a "business license" or an utility bill.

I thought the "business license" option is relevant, I provided the registration certificate with national trade registry (Romania, EU country), translated by a translator authorized by the Ministry of Justice.

They asked to send the document notarized also, I did so. Received the answer that Amazon is not able to check the info based on that document.

I opened a case, Sunju replied that the information on the document I sent are not matching the info on the Seller Central. Checked both info, they are identical, prepared a document with a comparison (screenshots) from both sources anyone to be able to easily compare and see there are the same data and sent.

Aneesh replied that the address in the document I provided is not matching the "official database". At least the issue seems reduced to the address... I asked to clarify to which "official database" are they referring to. The only official database for Romanian companies is the Romanian Trade Registry, the same institution that issued the document I provided and it's impossible to have other info on our company.

Divya responded this time, no response to the "official database" or "business license" matters, asked for an utility bill...

Going back to square 1...

In the meantime 3000 euro sales are blocked at least for 60/90 days and I already incurred 35 euros costs on translations which Amazon was not able to use...