Sennheiser HD 4.40 BT Not charging.

Sennheiser HD 4.40 BT Not charging.

I all started last month when I forgot to use the headphone for a week. So, when I tried to power it on, it wasn’t switching on. When I tried to put it in charge, there was no indicator, but I felt slight heat on right side of the headphone. I left it for few hours, then it started working, but after 2-3 hours it abruptly shut down without any warning.