How to open Plantronics Backbeat Fit headphones?

Hello,I have a problem with my headphones, they do not react to the charger. I want to unscrew them and try to fix them. I found help in this topic :

How do I fix my backbeat fit?

But I can't press the device out of its frame. Someone will help me?

I have one more headphones in which the red diode lights when charging and nothing. Hard reset does not help. Any idea?

Thanks :)