I have done business with these Canadian Retailer's websites;
https://silvergoldbull.ca/
https://www.colonialacres.com/
https://thecoinshoppe.ca/
In person (Vancouver, BC);
https://www.vbce.ca/
https://www.bordergold.com/ (website sales too)
This would be a good start I hope.
RE: Where to buy silver in Canada?