I would strongly suggest you don’t ship items to Amazon until you are fully verified. Amazon is notorious for having never ending cycles of robotic responses when issues arise and i can only imagine issues coming about if you ship your products to Amazon but they don’t end up authorizing your account.

I can’t see an issue with listing items fulfilled/shipped by you because if an issue did arise the listing would just become inactive and you wouldn’t have your stock stuck in a fulfillment center.

In the T/C it may mention something about this. I’d recommend taking a read of it just to be sure.

Absolutely second @TheWatchMan 's advice.
Do NOT send any goods to FBA until you have been verified since you will end up in all sorts of bother if they deny your application.
Settings up listings, however, is fine.
Please take the time whilst awaiting verification to go through all the “Seller University” videos found on seller central
https://sellercentral.amazon.co.uk/learn/ref=xx_su_foot_xx

and read the help files as thoroughly as you can so that you are as equipped as possible when you finally begin.
Good luck.

There isn’t any reason to send inventory into Amazon’s warehouses without even having your Seller Account activated, as there really isn’t guarantee you will manage to successfully pass the verification.

The initial Seller Account Verification can take anything from a few days to a few months. My first verification took almost three months.

Just patiently wait and provide Amazon any additional information or documents which they request.

Once your account gets activated, you can start sending inventory into FBA and setting up your listings.

Amazon verified / activated my account last Friday, not much changed though. Still won’t let me add products / create listings(‘Problem with your Seller Account’ error, how informative).

All looks ok in Settings > Account info:
Account status: valid
Current Status of Listings: Active (Listings available for sale on Amazon)

From Performance > Account health: ‘Your account has been deactivated.’

How does one can even make sense of this?

No reply from support yet.

Case marked as ‘answered’ and closed, with no actual response. Again. This is frustrating.

Should I appeal? The form asks for additional information though, I have no idea what else they may want from me.

Performance Notifications page:

Screenshot from 2019-09-23 21-05-06.png 1600×900 111 KB

Another template response from seller-performance@amazon.co.uk today:

Screenshot from 2019-09-24 14-24-28.png 964×189 24.2 KB

Still nothing since two weeks ago. My Account Info page looks like it’s all good, it’s only when I check Account Health there is an Account Deactivated message. This is way confusing and frustrating

Screenshot from 2019-10-07 09-33-53.png 1587×619 107 KB

This is plain stupid, 3 months and there have been nothing but template msgs from amazon. I’m deleting both my seller and buyer accounts.