you obviously don't know how utilities work, so i wouldn't be so quick to sass the OP. It's unlikely that her bills were 0 - utility companies charge a set rate just for using their services, and then with electricity, little things still end up costing money even in an empty unit - having a fridge and stove plugged in. Then there's the fact that a landlord is unlikely to leave an empty unit unheated (to avoid frozen pipes, condensation, etc), which is why there was still power in the apartment. if she pays for heating there's a good chance she was paying for heating in that empty unit which may account for the confusion.

I feel bad for you, my electric company did something similar. They did not send me a bill for about 5 months. I kept calling and trying to figure out what was going on and paying the amounts I was told I owed over the phone. Then I got a disconnect notice because I owed $700, obviously the amounts I was being told on the phone were not accurate but the $700 did reflect the payments I had made. We ended up not having electricity for 2 months because we couldn't pay it back and they were unwilling to work with us on a payment plan despite it being their mistake. To top it off we thought that we'd try to get th electricity back on by having my roommate at the time put the electricity in their name while I worked on paying off the other account. They told her that they couldn't open an account in her name until my account was paid off. Their reason? At one point I asked what I had to do so she could call if there were problems and I was not home. They said they just needed me to give them her name so they'd have permission to talk to her. I thought this was a good idea in case there was a power outage or if I went out of town and the bill had to be paid, so I gave them her name and permission for her to access my account. Apparently to them this means that she is now ON my account and is financially responsible for it. When she moved to a new place she found out that she actually had an old account from a few years ago in her name, they told her then that she could have just used that old account and not waited until the $700 was paid since she was a returning customer. Utility companies are dicks, commonly because you have no other option as far as a competitor goes if you are in a smaller city.