E.ON call centre staff were found to have misinformed 450 customers between October 2013 and February 2017 about the switching window, while 22,000 npower customers received letters saying they would incur charges between June 2016 and February this year. While no customers were found to have actually been charged those fees, E.ON has since worked with Ofgem to "put things right", updating its call centre scripts and paying out £21,000 to redress "misadvised customers" who either cancelled or delayed plans to switch providers as a result. Npower corrected the letter it sends to customers during the 49-day switching window and has compensated four customers who abandoned plans to change providers due to the misinformation. "Ofgem has closed these compliance cases without taking formal enforcement action, taking into account the steps that E.ON and npower have taken to improve their performance and the small number of customers who suffered direct financial loss due to the failures," the watchdog said.