Payment went through twice. Not a disaster, but the way it was handled tells you a lot about the operation.
Customs handling fees are charged by the carrier, not the state, which is why they are so hard to contest.
The reference number on the letter is the only way anyone will find the file again, so it goes in the subject line of everything.
Reading the statute rather than the summary changes the tone of everything you send back.
Canada Post scans are generated at the hub, so a silent tracking page is not evidence of a problem for the first 40 days.
Any experience with the equivalent in another country would help.
Check the register yourself rather than trusting the number printed on the site.
Split the order. Currently on a 3-D Secure prompt myself.
File early.
Be careful reading one parcel as a rule. Two successes build a false model.
Fees like that are charged by the carrier, not the state, which is why they are hard to contest.