Appalling company - Please avoid. I was a customer of ExtraEnergy 2 years ago. After a series of incorrect bills, overcharging and then failing to return a large credit that had accrued on my account I eventually sought help from the ombudsman who found in my favour. I gladly used the compensation I received to pay an early cancellation fee to leave the company. 18 months later Extra Energy contacted me to say they had incorrectly billed me and now wanted me to pay them more than £500!!.. After much stress and after pointing out my legal rights they accepted that they were wrong and said they would not contact me again. Amazingly they have now contacted me 6 months later to say they had decided that I still owed them the alleged debt. Please don't be lured in by the promise of cheap tariffs - do your research in the review forums and find a decent company.