Worst energy supplier ever. Got my readings wrong from day one. Never managed to correct it properly. I was overcharged for almost 1.5years (£90 with Spark and £40 with my current supplier). When I moved to another supplier, my account showed £480 credit. I had to contact them several times to receive my refund. When I spoke with them, I gave them again my final readings which reduced my credit to £370 according to technical support on the chatbox. 2 hours later, I opened my account again to see if they had updated my account and suddenly my credit went down to £270.