We got a very confusing water bill. It covered two different periods of time. They overlapped. By a lot. The bill was huge, close to twice what we're used to. I called the water department (doesn't that sound strange, the water department? how about the air department, the food department?). Anyway, in an uncharacteristic move for me, I asked polite questions. After weeks of dealing with ATT, I was way beyond being polite to any company but I decided to try. So I asked all the obvious questions and the rep explained the bills were for two different properties, our old house and our new house. When I looked at my calendar, I saw that indeed the water department had it right; we had possession of our new home before we moved out of our old house, the dates lined up. I said into the phone, "Boy, I'm glad I didn't start with my angry voice." She laughed. Hard.
Now, if only ATT had actually done things right, I wouldn't have used my angry voice with them, either.