My Sena SRL isn't very well

My Sena SRL has stopped taking any charge. I tried to top it up mid charge and noticed that the red light didn't come on. The device worked perfectly in all other respects until it went flat, and that was it. I have tried multiple chargers and cables with no luck. Has anybody experienced anything similar? I recently updated the firmware.

Not the srl but my last smh10, it did exactly the same I even went as far as swapping the good battery from my wifes smh10 and it still did not work or take charge, switch on etc.
Basically the unit was b#ggered so bought a new unit.
Ps the battery out of my original unit is now in my brother in laws smh5r and working perfectly.
SENA weren't interested as it was out of warranty and if you look online you will find similar issues with various sena models

Have you tried a factory reset?

My sena used to refuse to turn on and charge sometimes

poke a pin in the reset hole and see if a full reset cures things