RetaRick_CA ↑ said:

Living somewhere the domestic route does not exist, which makes most of the advice on this board inapplicable to me.

International shipping tracking for cross-border ordering orders: my experience with customs in the US when ordering from overseas:

Seized and destroyed — had to get a reshipped package.

Tips: always include a copy of your prescription, declare medication properly on customs forms, keep quantities reasonable (personal use = 3 month supply max), and use a vendor who has experience shipping to your country.

PurityPaulOR ↑ said:

Import rules are jurisdiction-specific and this board keeps giving US-shaped answers to non-US questions.

Adding the part of the answer the thread has not reached. The useful move here is to separate what is established from what is widely repeated. Those two sets overlap less than the confident tone of most write-ups suggests, and the second set is where nearly all the disagreement on this board comes from.

A narrower follow-up, since the general answer is now clear:

What actually works on a prior-authorisation denial, as opposed to the list of things that sound like they should work?

OP back with an update, since a thread like this is useless without one.

Follow-up — getting the denial reason in writing was the step that mattered. It named the criterion, and the criterion was a document I already had.