Your buyer has 30 days from the item's last estimated date for delivery to open a case for item not received.

Only a tracking number showing delivery will close the case in your favour.

If this is not available you will need to fully refund within 3 days so as not to receive a damaging defect on your account.

Just to ask was this by chance a GSP item?  Then, all that's need here,  is tracking to show delivery to the GSP location in the UK.  If it was a GSP item and tracking does show this and a case is opened,  make it clear in the case tracking Has shown delivery to the UK hub.

@hanveneklaasslot-0