No signal / how to contact Microsoft with direct enquiry

My TV keeps saying it is not receiving any signal when my console is turned on. I have tried connecting my xbox console to other TVs and used different HDMI leads with the same result so it's definitely my console that is the issue. Anyone else had this
issue? Also when I try to turn off the xbox console by holding down the light up button, it only stays off for a few moments and then turns itself back on. I have been trying to figure out how to send an email about my problem to Microsoft because my warranty
only just ended 4 days ago so I'm hoping I can get them to look at it without the $289 fee but can't find an email address or way to contact them so if anyone has any advice on this too that would be great.

:)