Hello,
This is quite random but I saw another user post about this problem and the thread had closed with no good conclusion because there weren’t any responses on it.
I’ve had my earphones about a year and they stopped changing properly. The left was fine but the right would only charge if the case was upright, then it stopped charging altogether and the LED wouldn’t come on when I opened the case, only flash green at random intervals.
I just cleaned the contact point with a pointy tipped silicone swap, but you could probably use a toothpick.
I cleaned inside the case and the bottom of the earbud itself and now everything seems to be working fine.
The lights are showing up normally. I’ve got a run in an hour so I’ll see if they charge up by then and hopefully will remember to update.
I’m forgetful so if there is no update assume that it has worked 
If it doesn’t work I will be reminded to update by my frustration haha