I realise that it's of no use to you regarding your problem, but whenever a utility bill arrives it pays to check the meter reading and write it and the date on the bill. The reading will not absolutely match that on the bill, but it's easy to spot when things start to go wrong. I would vigorously challenge the bills that EON have said the actual readings were altered to make them coincide with their expectations, if they can do this what is the point of a meter?