Last time I ordered from Ecowitt and shipped by Yunexpress, it went through customs and I didn't have to pay anything. It was a somewhat small box.
For a lot of overseas shipping to Canada, you can get 'customs exception' where it will just take time for the package to clear. I've had this happen numerous times with different shipping companies and never had to do anything, just as Ecowitt told you.
If you do end up owing customs tax, it is possible to go clear it yourself at the airport or other designated customs facility. Based on your availability, distance to such facilities, and amount of taxes it can be debatable if it's worth it.