Pro/freight bill number - help

Greetings,

I have sent my shipment to the UK, not yet to the Fullfilment center, and Amazon asks for a Pro/Freight bill number. What is this number, the carrier doesn’t know. Is it the tracking number? Can someone give me details on what this number is and where to find it?

When I logged in, Amazon showed this:

When i clicked “Import entry number incomplete” it showed this:

Have i done something the wrong way? Amazon Seller Service is non-existent.