As this is your first post, welcome to the Pure Planet community! That's made up of all your fellow customers, many of whom are happy to help out where they can.
I'm not an expert on meters, but I'm just wondering whether this is a smart meter readout that stopped working when the previous owners switched to Pure Planet. Is there a source meter where you can see a sensible figure?
There's advice about reading meters here
If this doesn't help, come back and ask again, plenty of people will be willing to help