It does seem weird this has happened for just the one issue.

I don't suppose there are any emails in your junk folder from eBay questioning whether you are using the correct type of account and strongly encouraging you to sell your camera bits on what they call a  'business' account.  They were doing this a while back to some sellers listing many items on a 'private' account.

If it is just your collection you no longer want to keep to use, then this 'private' account is correct. 

However you did say it was because you had dropped to below standard. So a strange one really.