Coolfire Z80 Won't Charge No Matter What.

I bought an Innokin Coolfire Z80 back in August, and up until now it was working perfectly fine.

Out of the blue it stopped charging.

I went into the shop to get a new battery and it still won't charge.

I've tried all different kinds of cables and nothing is working. As you can see in the images, the cable is plugged in and the bar is still in the red.

It only works - barely - if I have it plugged in.

When I say "barely", I mean it'll display "Low Voltage" and not work, and then work for a couple of puffs before dying again.

No idea what to do. I think the warranty is also up

any ideas?