We've had a disastrous experience with Ecotricity. They overcharged us for £3000. After complaining, they brought the bill down to £1700 and after complaining two more times, we eventually arrived at £35. I wonder how many people have been overcharged by them and didn't spend hours and hours arguing on the phone, double-checking calculations, sending photo evidence and angry emails to eventually resolve the issue. The service was often extremely rude and unprofessional; we were repeatedly asked to just pay the bill as the issue was already resolved from their perspective. We sent a complaint to their complaint system and received a patronising stock response without an apology. Disappointing!