Send the agreed spare-kit lines with the receiving shortfall. Ask for actual availability and standalone dispatch terms, not another assurance that the installed pendant has its cable.
Have they named that consolidation booking, or is it only a possible future route? I would ask for an alternative if they cannot give an actual supply plan.
That could be a practical option, but compare the correct local replacement and lead time too. A credit that closes the order may still leave maintenance buying an unsuitable or unavailable spare.
Then the decision is visible at last: wait for a real supply plan or negotiate the credit against an identified alternative. The old next-shipment phrase didn't even let you compare those choices.