How to Contact Telus Without a Canadian Number?

I recently moved out of Canada, and Telus is charging me for not returning their router, even though I have the Canada Post receipt as proof I have sent to them.

The issue is, I can’t find an email to contact them, and their live chat keeps asking for a Canadian phone number, which I no longer have.

Has anyone dealt with a similar situation? What’s the best way to reach them from outside Canada?