Apparently this has been an issue in Ontario:

https://www.ontariorvda.ca/what-we-do/rv-regulations/

Supposedly "resolved" now, but you may have some challenges. You might try visiting an RV dealer near you and just asking someone who they use.

...r

On 2019-07-18, 9:04 PM, "Vanagon Mailing List on behalf of Jeff Palmer" <vanagon@gerry.vanagon.com on behalf of w.jeff.palmer@ICLOUD.COM> wrote:

    In Manitoba :) I couldn�t find anywhere that carried propane last time I was there. 
    
    Sent from my iPhone
    
    > On Jul 18, 2019, at 7:37 PM, Andrew Berg <andrew@bergweb.ca> wrote:
    > 
    > Where does everyone in Southern Ontario get their tanks filled? Have never refilled mine. Can you take it to any fill station like a canadian tire gas bar?
    > 
    > Andrew