I’ll speak as an Etsy seller and as a Canadian: As soon as I notice the order, I always send a copy of my convo to the e-mail address simultaneously if there is a problem.
My processing time on Etsy is 1-3 days: If I don’t get an answer within a day, I send another one (both convo and e-mail), with the added information that I’d have to cancel their order if I don’t get a reply until the next day. My third and last convo&e-mails mention that I have to cancel their order right after sending this message, info about the next steps, and that they are welcome to shop again when they see these messages.
Most of the time, I receive a reply within 2 days and I can ship the order on time.
Most Canadians know about the duties, taxes, and handling fees. AFAIK, this is the latest about the De Minimis Thresholds:
Where I live, UPS/Fedex/DHL arrives quickly and I pay every penny through my accounts, most of the time automatically, before the package is delivered.
When a package is shipped with USPS, Canada Post takes over after the border and I pay Canada Post for duties, taxes, and handling fees. To be honest, sometimes Canada Post doesn’t charge for these if the value is under CAD200. Probably, when they are too busy… So, if I order something small from the US and it’s not urgent, and if it is under CAD200, I prefer USPS. The shipping cost is less than the others and there is a chance that Canada Post might not bother to collect the duties, taxes, and handling fees and just leave the package in my mailbox
I’ll object to this though:
Yes, Canada Post does not call but the note they leave either at the doorknob or in the mailbox is enough, and they leave another note if the package is not picked up within 15 days IIRC.