It resolves itself, and mostly without you.
What happens, and when
A buyer who won while watching has thirty minutes. One who won while away has twelve hours from first opening it.
When that passes: the order is cancelled, a strike is recorded against them, and the item is offered to the next bidder at their own bid. They get twelve hours, because they were not expecting it.
You do not have to do any of that.
What you should not do
Do not chase them off-platform. A WhatsApp conversation about a Metzee order has no record, no protection, and no standing if it goes wrong — for you as much as for them.
Do not take payment directly. You lose the protection you are paying for, and it is reportable.
Do not relist it immediately. Give the second chance a chance; the under-bidder wanted it.
If it keeps happening
A pattern of non-payment is something we act on. If one buyer is repeatedly doing it, say so.
While you wait
Pack the orders that did pay. Most winners pay within minutes, and the ones who do not are a smaller problem than the time spent worrying about them.
Questions people ask
Do I get the item back?
It stays yours. If the second chance is declined, relist it.
Do I lose anything?
The sale, and the time. There is no charge to you.
Can I block a buyer who does this?
Report them. Repeat non-payment is handled centrally rather than shop by shop.
What if they message saying they will pay tomorrow?
The window is the window. If they genuinely want it, the second chance or a relist will find them.
Next: what happens if a buyer does not pay, from their side.