Almost every argument about a late package comes from adding up the wrong numbers. There are three intervals and a listing usually quotes one.
Payment confirmation, which depends on the coin and the network rather than on anybody involved. Handling, which is how long the seller takes to dispatch after the money clears. Transit, which belongs to the carrier. A listing quoting two days almost always means handling, and the total is all three added together.
Domestic post moves on a schedule that can be estimated. Anything crossing a customs boundary enters a queue whose length nobody outside can see, and it can sit there for a day or for a month with no visible difference. Ordering across a border means accepting an interval that cannot be forecast rather than one that is merely long.
Past the slow end of all three intervals with no communication. Not past the handling time, which is the most common false alarm, and not past what you hoped. If the seller has been in contact and the automatic release timer is not close, waiting is still reasonable.
Carriers slow, volumes rise and customs queues lengthen at the same time. A handling estimate that is honest in March is optimistic in December, and a window that usually holds will not. If timing matters, order well outside those periods rather than trusting the same numbers.
Whether the listing states a handling time at all, and whether recent feedback mentions timing specifically. A seller who states a window and beats it is worth more than one with a higher rating and no stated window, because the second gives you nothing to measure against.
Handling is the only interval a seller controls. Quoting a total would mean promising something that depends on a carrier and possibly a customs queue, and a seller who does that is either optimistic or careless. Reading the quoted number as what it is removes most of the disappointment.
Order with enough margin that the slow end of the range is still acceptable, then stop checking. Watching a window you cannot influence produces anxiety and no information, and the anxious version of a buyer is the one who messages too early and confirms too soon.