If the place is currently empty you can give the current supplier a final (to the previous owner/tenant) reading so that they can bill them.
You pay whatever is used from that reading onwards
Provided it wasn't a fixed term tariff you may have the option of signing up to a new variable or fixed tariff
if you want to switch providers you'll need the meter number(s) and the reading. If you have an old bill from the previous owner/tenant you should be able to negotiate a monthly payment based on likely energy use.
Or that could all be *******s