We ordered 120 matched accessory kits, each including a tool cable. Stores counted 108 cables in the sealed delivery. Seller counts 120 bags and calls the order complete.
Send the required and received count for each component beside their confirmed per-kit contents. Ask them to answer the twelve-cable shortage, not the number of bags that reached your stores.
Ask for a standalone supply offer for the acknowledged shortage, with the cable reference and shipping covered explicitly. You should not need to invent another purchase to discuss the one you already made.