Check your physical bill for any other company names other than PSE&G...you could be paying a totally different company for your energy supply.

Once I had an extremely high bill from PSE&G, and there was this weird company name on it. Turns out I had been switched to another private energy supplier. They can charge whatever they want, and can even raise the price of an average kilowatt hour at any time.

Not saying this happened to you, but wouldn't hurt to check. Also, know that those wall mounted combination heating and cooling units that come with many luxury buildings are very inefficient and costly. In the winter and summer months, you have to run them constantly, and they gobble up energy like a Pac-Man pellet! Best wishes! hopefully it was a misread of your meter.