Has anyone tried the "bill by email" from Bhutan Telecom?

Bhutan Telecom mentions on its website that bills for a fixed line can be emailed to you. Their "e-billing" webpage reads:

Have your Telephone Bills sent by email. Send your details to bia@telecom.net.bt. 

Has anyone tried this? What are the details that you need to send besides the phone number and your preferred email address? How do they verify that the email indeed belongs to the holder of the account?