Microsoft Elite Controller will not connect to my Xbox One X

At my wit's end. I have an Xbox One X and a Microsoft Elite Controller. I have had the controller for 2-3 years now and just a few days ago it started disconnecting. I was able to hook it up to a USB cable and it would work fine. Then, last night even that
stopped working. With batteries in it, attempting to connect wirelessly, the Xbox button just flashes steadily without connecting. The last times I WAS able to get it to connect, the Xbox said the controller needed an update. Two times I attempted to update
it and it stopped each time on 45%. Now it just won't connect. I have already tried everything I have found to get it to connect:

• Attempt to connect wirelessly as usual
• Attempt to connect via USB
• Attempt to re-pair the device to the Xbox
• Hard reset Xbox
• Unplug Xbox for several minutes and reboot
• Various button combinations on the Xbox and/or controller
• Attempt to connect the controller to a Windows 10 PC via USB

I have tried using the "support" pages. Nothing suggested by the automated systems has helped. I have also tried the option to send messages to players without success. I also just sent a Tweet to Xbox support, since this is as close as you can get to actually
contacting someone from Microsoft for help apparently. I didn't see a live chat, email or phone number to contact them directly, just message other users, this forum or a tweet. :/

Has anyone else had their controller disconnect this badly and find a way to get it back? This is the most expensive controller I have ever owned and it is also the only one I have ever had die on me. Like I said, it IS 2-3 years old, but I have had plenty
of other standard Xbox and PlayStation controllers last longer than that. Thank you so much if you know a super secret trick to fix this.

:)