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1. Confirm that the charging case has sufficient power. 2. Put the faulty earbud into the charging case and confirm that the red light of the charging case is on and stays on, instead of turning green after a few seconds.
3. If the red light turns green within a few seconds, reposition the bud. If the red light continues to light up as in step two, go to step four; if it turns green again, repeat step three.
4. When the red light remains on, wait for about 30 minutes; the charging case will charge the headset to 40%–50%.
https://www.reddit.com/r/galaxybuds/s/N5qwHFgIdFMaybe try factory resetting the buds.
Open the "Galaxy Wearable" app on your phone, navigate to your earbuds' settings, and select "Reset" to initiate a factory reset; this will clear all previous pairings and settings, allowing you to pair them again with your device.
Please note that, in the worst case, your buds are under warranty. Samsung normally provides DPD to pick up from your address (or, if preferred, drop-off at a postal service) and then deliver them back.