right,
the first thing is to knock down the main breaker to the property, the meter should stand still.
if not, that means somebody is hooked up to your connection after the Meter and counts on your Bill.
in case the meter stands still there are 2 possibilities:
* you installed a machine during the last months which consumes much higher than the prior, I had that myself this year due a "great Deal" for a new heater, my usual Bill of 2.500-3.000 went up to near 5.000 2 consecutive months, yep, it takes a while befor you recognize such and find out the reason, 1 month after which you get the 1st high bill, 2nd month running while you still think about that 1 high bill, 3rd month after you got a clue about the 'may be' cause with the heater shut down/I put him on a separate breaker, to turn on when needed and turn off after the shower, darm , that worked, so the 4th month Bill been on the usual Nivel.
* the 2nd reason if that meter stands still could be simply because the person hooked up to your power is not using it at that Moment. maybe because it is a hook up of a nearby construction that has at that moment no electrical machine running, or you ordered a check by your local Power supplier, who of course shows up at your place with their company car with big letters written on that, so the bad neighbour shuts his consumption down for the short time of 'checking'.
I would recommend to check the meter-thingy with the breakers down a couple of times, at different hours, and don't tell your neighbours what you are doing or that you comlalin about such.
Mike