I can't remember if this is for all electrical companies, or just one or two, but I did read that they only have to read ONE meter per year, and just guestimate the others. Sounds like that is what they're doing. Unfortunately thought with them guessing the meterage during the year, it could be way off. You might get 2 or 3 largish bills, but then the 4th quarter will be a lot less as that's the accurate one.
Good luck, it does sound like it's going to be a fairly large sum.
Really? the meter maid comes out every 3 months and reads our meter and we're rural!

I would be taking that up with an ombudsman, because it is not your fault that the meter was faulty and it isn't your responsibility to get fixed.