Charge 3 won't pair with my phone

[LB101]

Today my husband received a replacement Charge 3 for a faulty one that was bought in May 2020, (the screen was faulty and just scrolled constantly then stopped working completely.) 
The replacement does not appear to be working properly. I can not pair it to the android phone that worked perfectly with the  previous charge3. I have re installed the app, signed in etc but the phone still can not find the Fitbit. The Fitbit is showing the Fitbit logo on the screen and www.fitbit.com/setup but not appearing to respond when the side button is pressed or held in, there is no green light showing on the back of the watch. I am very disappointed.

The replacement did not arrive in a Fitbit box, I am starting to suspect its not actually new. 
I would appreciate any help in trying something different to get it up and running. 
thanks in advance

Moderator edit: updated subject for clarity

[JuanJoFitbit]

Hi @LB101, welcome to our Fitbit Community. Regarding the pairing issue that your Charge 3 has experienced, I appreciate the time spent trying to get it resolved before contacting our forums.

Please restart your Charge 3 as described in this help article. After this, make sure that you are following the setup process as instructed in this help page and see if your tracker connects with your phone properly.

Keep me posted on the outcome.

[LB101]

Thank you.
I have followed the steps you advised. The phone found the Fitbit and started the updates, The Fitbit appeared to be updating then stopped and showed either a i or ! On the screen before reverting to the Fitbit icon and www. Fitbit.com/ setup.
I retried the steps and had the same results. I also restarted the phone. I am at a loss.
The phone worked fine with the previous Fitbit.

[JuanJoFitbit]

Hi @LB101, thank you for trying the steps previously shared. I'd like you to try one more workaround, which has been helpful for this type of issues. Please try a long restart. To do so, follow the steps below:

1. Connect the device to the charging cable. 
2. While the device is plugged into the charging cable, press and hold the button down for 15 seconds. 
3. The device turns on and shows a battery icon. Two vibrations occur: first a short vibration, then a medium vibration. 
4. The device turns off.
5. The device turns on and shows a progress bar and short vibrations occur. The progress bar completes. Note: A total of 7 short vibrations occur. 
6. Remove the device from the charging cable. The device shuts down.
7. Important: Plug the device into the charging cable again.
8. Set up your tracker from scratch again and see if the issue gets fixed.

Let me know how it goes.

[LB101]

Hi
The device does not respond as you described. There is one vibration, the screen shows a smiley face then returns to the Fitbit Logo.
After a while I retried the procedure, the screen shutdown and will not restart.

Regards.