Receiving has that already. The seller keeps answering the commissioning email instead, as though a working installed cable settles the missing spare.

Use a separate subject and ask who owns fulfilment of the outstanding kit.

Done. I listed the spare reference and left the installation questions out. No new order attached to it.

I wouldn't say they have confused the cables deliberately; ask them to confirm the outstanding quantity in their own reply so you can see what they actually accept.

Any acknowledgement of the shortage now, Ben? Or just another reply about the robot working

They acknowledge one spare kit outstanding. Still 'next shipment'. That's progress on quantity, nothing useful on when or whose shipment.

I'd ask whether it is in stock before arguing about freight, because we spent ages discussing delivery for something the supplier hadn't obtained yet. It didn't make the wait shorter.

And get a contents list. A kit acknowledgement can still conceal a missing cable.

Hana, stock status is unanswered. Aisha, their acknowledgement names the cable and the other kit contents. I've asked for a standalone supply date.

Keep stores told. Someone will read package received and think the spare is on the shelf

At least the outstanding contents are explicit now, Ben, but I wouldn't put a date on your maintenance cover until that separate supply question gets an answer.