Hi Northlea, sorry to hear about your awful experience with Endesa.  I'm confused as to where they got this figure of €300 from?  How can they bill  you if they havn't taken meter readings?  How can you have paid the bills for the past 4 years without giving them a meter reading?  It seems to just be a communication problem unless they have underestimated your actual electricity usage over the past number of years.  That happened to a neighbour of mine who doesn't live there permanently - they would visit for a number of weeks each year but Endesa couldn't read the meter so they only applied the standing charges for a few years so when the meter reading was finally given - they had a mighty high bill :'(