After them increasing my Direct Debits on what felt like a monthly basis for the best part of a year, I finally got round to checking the readings a couple of months ago to discover that they'd all been estimated (Do BG ever bother to send meter readers round now?). As dh & I are often at home at opposite times I assumed he'd been in when the meter reader had been.
Anyway, we had gas central heating installed last winter so surprise, surprise, they'd grossly overestimated our electricity consumption and underestimated our gas consumption.
I tried to submit correct meter readings online but, while they were happy to take the increased gas reading and alter my bill accordingly, they wouldn't take the electricity reading. Phoned the call centre and eventually after about 45 minutes on the phone they worked out that they owed us three full quarters worth of electricity payments, which balanced with what we owed in gas meant we owed them £75 (our electricity dd up to that point had been increased to £100 per month).
All good, and for about 24hrs this change showed up on our online account. Until suddenly they decided to reverse it for some reason and then took £380 out of my bank account - two days before pay day. Luckily I've been saving for mat leave otherwise I'd never have nearly £400 two days before pay day.
Obviously the previous 45 minute conversation was denied when they were phoned again and they said it would take at least 10 working days to give me my £300 back. In the meantime they tried to increase my electricity direct debit again (you know, the one that was already so high that I'd been giving them money for nothing for three quarters of a year).
It's sorted now. I do my own monthly readings and pay them what I owe to the penny. I'm never going to get suckered into equal direct debits across the year again. They are utter, utter incompetents - but only ever in their own favour.