My headphones won't charge?

Not asking for jbl E45BT but the Jbl duet nc model doesnt come up.

JBL DUET NC

Working perfectly before, thought they had full charge because the red led light didn't come on when i plugged them in. They just ran out of battery and have stopped charging. I have tried the charger on other things eg. Phones and it works fine but the headphones still wont charge.