Can a fitted cable also count as the promised spare?

Order attachment says one installed plus one spare, so I've returned a marked inventory with both positions stated separately.

That wording is useful. Ask for confirmation of the outstanding item and how they intend to supply it. There's no ambiguity left about whether the cable already plugged into the tool is the spare sitting in stores.

Seller acknowledged one outstanding cable, but replied next shipment with no other detail; at least the arithmetic is no longer under negotiation.

Ask which shipment. Or more usefully, its planned dispatch and the cable's item reference.

Yes, get them to connect the promise to your particular item. A shipment can leave their warehouse without your cable on it, so a general freight schedule is not the missing evidence.

Does the item reference distinguish the cable length and connector arrangement from similar stocked cables? Resolve that from the accepted tooling information before another parcel arrives containing something merely described as a robot cable.

Worth doing. Our first replacement was the wrong variant, which turned one missing item into two delivery conversations. Send the reference from the accepted assembly and ask them to confirm that exact spare.

Integrator supplied the accepted cable reference and seller has confirmed it in writing; still no dispatch record.

Fair question, and I was too quick to call it an inventory dodge. A mispacked cable would be less dramatic, and rather more useful, than the argument we're imagining.

Stores checked the retained packaging against its arrival photos, no spare cable; seller now says it is awaiting stock, rather than already packed for dispatch.

Then you've established the shortage and the current supply claim. Keep it open under that cable reference. Let us know when an actual dispatch or alternative arrangement appears; 'awaiting stock' is clearer, but your shelf is still empty.