Green Star Energy

I gave regular meter readings online throughout the year so I believed my quarterly bills throughout the year should have been reasonably accurate. I was feeling quite pleased that my account seemed in a healthy credit but right at the end of the year they recalculated again and deducted a further £700. Bills were incomprehensible. Decided to move on to new supplier and have asked for my balance back. They state that balance refunds aren't automatically generated when an account is closed and the customer has to ask for it!? They have my final readings, verified from the independent 3rd party but still won't give me my money. Their customer service is also ignoring my emails now. Stay right away from GreenStar.