Do you contact the customs office or the carrier first?

Domain age is one of the few signals that is expensive to fake and free to check.

Photograph everything.

Split orders. Two small parcels beat one large one for reasons that have nothing to do with price. Not on a controlled medicine on a flight but the pattern is familiar.

The published rule and the enforcement pattern are different documents. Only one of them affects you.

“Dispatched” means the label was printed. That is the entire meaning of the word.

Do you contact the customs office or the carrier first?

The declaration contradicting the return address is what gets it opened.

What do you do about the fee? Do you just pay it?

Photograph everything before you open it. Ten seconds, settles most disputes.

Same here.

The address matters more than the contents eventually. Changing what you order when the address is flagged changes nothing.

Same here.

If you name a shop here, say whether you are affiliated. First line is enough.

Written confirmation email after every phone call. Cheapest insurance there is.