Originally Bulb, who unsurprisingly went tit's up. Now Octopus, who took over Bulb in December. They're still incorrectly billing me, despite my further attempts to come clean.
I had a smart meter fitted 3 years ago and since then I've only been charged the standing charge portion of my gas bill, never for the gas itself, despite me reporting this error and sending manual meter readings.
Fortunately, due to Ofgem's back billing rules, you can't be billed for gas or...