Student or Learner
The factory claimed the sorting fee of USD xxx. This is the extra fee for sorted out the uncertain / unclarify goods from last shipment.
'Unclarify' is not a word.
'Unclarified' is, however, and is an adjective, meaning 'not made clear'.
Also, you cannot have 'uncertain' goods because that would mean the goods had feelings and on that day felt uncertain .
Therefore I would recommend: 'This is the extra fee for sorting the unclarified goods from the last shipment.' This means that those goods were not labelled or had not been written up in the despatch note, or something similar.
Is that what you want to say?