Why did the LED behavior of the case change?

I've had these head phones for a few months now, and suddenly the LED behavior of the case changed.

First, when charging it (fully), or putting the ear pieces in, it just showed red anymore, where as it should show green. (Head phones still charge in the case, also when its not connected to a power outlet.)

The next day, the LED of the case wouldn't work anymore at all. No matter what I tried (e.g. factory resetting by 2 times tapping and then a third tap + holding for a few seconds).

I downloaded the JBL headphone app hoping, there would be a software update, but that app doesn't support this model.

Is there something else I could try or just live with the fact, that with JBL products under 100€ I'll be constantly running back to the shop? (Had the JBL Tune 215BT 2 times before, but the rubber cover that goes into the ear always came off after a year of using. Tried to glue it back together, but that didn't work very well.)

Update: The in ears wont load anymore, and so it seems something must be wrong with the power supply to the case. The female connector seems pretty clean to me, but I will try to clean it with flatter carved wooden toothpicks. The cable can't be the problem because we load our phones with it.