My stepfather passed away in May 2018 and used Greenstar for both his gas and electricity. The house sold a year later and I received a final bill for almost £1000 despite the utilities being turned off shortly after his death. I took photos of the meter readings at the time which greenstar have accepted but 13 different final bills have been generated with differing amounts and even £56 in credit at one point. Their staff are unhelpful, rude and terminate the call if they don't like what you say or question their calculations etc. 17 months later, the matter has been referred to the Energy ombudsmen who say it could take months to get resolution.