Unfortunately continually posting on the forum will NOT get you any help. We are all just other sellers and have no access to your seller account. The only way a forum moderator might intervene would be if you tag them in to your post, but even then they have very limited options to actually do anything - it is usually just passing it on to the relevant department. You will have to deal with Amazon directly.

Have you opened a case with Seller Support (Help) as that would be your first step ? - cannot guarantee that any response would be very helpful, but you must do that first. Then you maybe need to consider mediation - .this is an Amazon service they offer.

I see you have already started 3 separate threads, and none have had replies, because none of us can help.

You say you have removed your inventory, yet they have retained some. Also that you downgraded yet are still being charged. Are these charges for FBA storage fees, or for the monthly professional selling plan fee ? There's a few things don't add up.

You say you cannot close your account - was the account deactivated for any reason ? - if so you cannot close a deactivated account, you need to get it reactivated to be able to close it properly.