Thank you for your post and welcome to the community.
I am sorry to hear you are having this issue. May I ask if you are placing the headphones into the charging case correctly as once they are placed into the case, they should go into charging mode which should disconnect them via Bluetooth. However on your mobile device, it will still show on your Bluetooth list as paired, but disconnected. this allows the headset to connect to that device when they are removed from the charging case.
I would advise to reset your device. to do so please follow these steps -
Place the earbuds into the charging case
Plug the charging case into a wall outlet using a USB charger and wait 5 seconds
Unplug the USB cord from the charging case and wait 1 minute
Remove the earbuds from the case and try again
If after this you still encounter the same situation, I would then recommend to contact your local Customer Support Team for further assistance.
If you select this link - Contact Us, you can select your region. Scroll to the bottom and select contact us which will provide you with their contact number.