The seller's final message explicitly includes the spare controller cooling filter. After checking our retained packaging and accessory list, I can account for the normal setup components but not the spare kit.

Send that message with your inventory. Ask for the spare's part code and whether it's dispatched; if so, request the parcel reference.

Am I giving this too much attention when the main package is here? The seller's wording makes the spare feel like an optional favour rather than part of our agreement.

On a different accessory purchase of mine, I described the spare as an outstanding order item. That kept the request proportionate to what had actually been omitted.

An outstanding spare-kit item is an accurate description. With the main package complete, the missing spare shouldn't affect your plans for loading sample trays.

You don't know their maintenance plan. A missing spare can affect readiness even when the installed hardware is complete.

@JamieBrooks0817 You're right. I can say the installed package isn't missing that component, but I can't judge your spare requirements. Keep that planning decision separate from the delivery count.

What I need is enough information to decide our spare provision. An indefinite promise of inclusion in another shipment doesn't let me settle that plan.

@NaomiChan1115 Wouldn't identifying the robot model be enough for the seller to select the spare?

You need the spare for your supplied configuration. A confirmed code tells you more than 'an extra' or 'the usual kit'.

@NaomiChan1115 The seller's follow-up messages promise inclusion without identifying the spare's code. That's part of why the repeated reassurance isn't resolving the issue for me.

Have the seller identify the shipment referenced in that promise. Until they explain whether it's booked and which order it serves, the phrase doesn't specify a completion arrangement.

Would combining the spare with another purchase be a sensible way to obtain it?

Don't assume another purchase is necessary. Ask how they'll complete the existing commitment before building a new order around it.

@JamieBrooks0817 I'll ask for a way to complete the existing order. I don't want the unresolved spare commitment driving an additional purchase.

@CallumAdams0099 Request a written description of any alternative item or order adjustment. A defined proposal gives you something to evaluate against the original spare commitment.

The promised spare kit has arrived, including the extra controller cooling filter, and I've checked it against the agreed contents and applicable identity. That closes the shortage.

@CallumAdams0099 Good, that's the promised item accounted for and checked.