First check your bill and see if both the previous reading and the current reading are ACTUAL as opposed to ESTIMATED. I have seen some pretty odd "estimates" on my bill.
Next, check the "current" reading (not "electrical current", but current in the sense of "now") on your bill against your actual meter. I've had the electric company misread a digit several times. If your meter has rotary dials be sure to read them carefully. On many of them
1/2 the dials are counterclockwise and the other half clockwise.
Also be careful when a "needle" is just about right on a number. When this happens you have to check the next dial to be sure of what the reading is. If the next dial is still on 9, then the questionable dial hasn't reached the number it appears to be "on". Depending on which dial is misread, that could cause a large change in your bill.
A couple of decades ago I lived alone in a small apartment and wasn't home much. I received a bill saying I had used 1069 KWH that month. I checked my previous bills and none were for more than 75 KWH. I called Con Edison and explained to the woman that the meter reader had obviously misread the "thousands" digit on the meter.
She asked me if I had an air conditioner. Nope. A fan? "Do you really think a fan would use 1000 KWH?" I replied. "Well you know that electric bills are higher in the summer..."
She grudgingly gave me the credit but not without giving me a stern warning that if the next reading showed I had actually used that power they would still bill me for it. I didn't worry.
Greg Guarino