It is possible that your account was a single-user account. This means that your account only has one admin, and no travel organisers or bookers. We close single-user business accounts because personal accounts are better suited for the needs of an individual user.
You can create a Business account again by clicking on your name on the top left corner of Booking.com homepage, selecting ‘Add a Business account’ and following the instructions. Please remember to add at least one other user to your business account.