Trying to cancel my account from another country

Hi, 

I signed up to Xfinity (for both internet and mobile) when I was living in the US for college. I recently graduated and moved back to my country but forgot to cancel both my plans. Now I want to cancel them but can't find a way to. I tried calling the Xfinity customer support a couple of times and couldn't reach a sales person + calling from another country is costly and hard. I also tried to find an e-mail to reach out to but haven't yet.

What can I do to cancel my account? Could you guys please help me out here?

Best.