Screen went black with only a tiny rectangle with five dots

[Avantha]

Screen went off. What I see are five dots in a tiny rectangle with the third in green and the rest white in color. The battery is good at 75%.
How can I get it to sync once more.

Bought this last 27th. in London and now I am back home in Sri Lanka.

Moderator edit: subject updated for clarity

[DavideFitbit]

Hi, welcome to the Fitbit Community forums, @Avantha. 

Thank you for all the information provided about this inconvenience with your Charge 5. 

If you haven't done so already, please make sure that you've completed a three pulse restart:  

1. Connect your device to the charging cable. For instructions, see How do I charge my Fitbit device?
2. Press the button located on the flat end of the charger 3 times (end of the USB cable), pausing for 1 second between presses. Then wait 10 seconds or until the Fitbit logo appears.

If you continue to have this problem, you can also try setting up your Charge 5 as a new device in your account and changing the clock face option on your device. 

Hope this helps, I'll be around.