I don’t know if my answer helps, it was strange even for me but it worked so I will share it.
I have a PEAQ bluetooth box (quite cheap really) and I put it on charge all night and woke up finding it wasn’t charging at all. I plugged it in and out and in and out and it stays on red for a bit then goes completely off each time. I kept fooling around with the buttons and pressed the two buttons (button for forward and button for backward) at the same time for about two or three seconds and then it shut off and when I clicked on the play button (turn on button) this time it worked. It’s so random I have no idea if this helps but since it worked for me I’m sharing this trick.