On a package I helped receive, separate close-ups identified the hardware but never connected it to the demonstration. Ask for a continuous view linking the package markings, fitted adapter and your samples through the agreed task. Keep the useful movement footage, but list what it leaves unseen.
Send a still showing that missing view and ask them to identify the fitted assembly. A longer version of the same camera angle would leave you with the same question.
Does the agreed trial name the destination tray? Otherwise they could show placement somewhere convenient and still omit the awkward part of your sorting task.
Then leave the demonstration outstanding against those specific views. Has the seller said who will arrange the recording, rather than simply forwarding your request again?