Fitbit Charge 3 black screen

[Fxt84]

Hi there, my Fitbit charge 3 has randomly stopped working. It’s still tracking data (sleep, steps etc) but the device is totally useless as a watch as the screen is totally black. I’ve tried rebooting it multiple times and recharged it etc - it still vibrates but the screen remains black. Nothing happened to it; wasn’t dropped and hasn’t got wet. I bought it on the 22nd November 2019 brand new from Amazon UK so it should still be under warranty for another 3 days. How do I go about making a warranty claim requesting a replacement? There doesn’t seem to be an option on the Fitbit website. Thanks.

Moderator edit: updated subject for clarity. 

[AndreaFitbit]

Welcome to the Fitbit Community, @Fxt84. I'll be happy to assist with your Charge 3 inquiry. Thanks for letting us know that you've tried rebooting it and recharging. 

Before proceeding with the Warranty,  please confirm that you have tried changing your Charge 3 clock face and  the long restart. After trying the restart. 

I'll be waiting for your reply.