Problem with my xbox one sync button
So the other day i turned on my xbox and my controller wasn't connecting to it so I tried replacing the batteries and everything e.g. using the cable to link it and then I tried using the link button on the controller were you press it on the controller and on the xbox. When I press the link button on the controller it flashes but when I press the link button on the xbox it doesnt flash, I also have a spare controller which also doesnt sync so it is definitely the xbox that is not working. I have tried all the troubleshooting for the sync button problem and have contacted microsoft and they said the only way to fix it is to send it to repair but my guarantee/warranty has finished ages ago so would cost alot of money to repair through microsoft. Do you guys have any ideas on how to fix this or what I can do?