Our arm crate arrived with an accessory carton strapped beside it. That carton contained brackets and packing pieces, not the controller or its power lead. The seller says those shipped separately but has sent only the reference for the arm.
I've kept the unpacking photos and both cartons. What would actually establish that this supposed second shipment exists?
Ask for the package identifier and evidence of carrier acceptance specifically, since the order list establishes what was sold rather than what left the warehouse.
Done. Also sent a photo of the accessory carton contents because their latest reply seemed to assume we hadn't opened it. We had; it was included in our original inventory.
Give purchasing the incomplete inventory now; installation planning should not keep treating the controller as a parcel that will certainly turn up tomorrow
The packaging detail is useful. It closes off one possible misunderstanding without pretending to locate the controller. Keep the missing items listed individually and ask the seller to reconcile them against an actual dispatch record. I would not infer more from silence alone.