cancel my Xfinity Internet service when I am outside of USA

I have permanently relocated from USA to other country, and would like to cancel my Xfinity Internet service.

I am unable to call 1-800-934-6489 from my current location because the toll-free number is not connecting.

Please help me process the cancellation through this messaging service. I would also appreciate confirmation of the cancellation effective date, final bill, any refund due, and equipment return requirements.