@Nathan2268
Why is the guest bringing/using his own Electric heater ?
You should not allow it, assuming there is one present in the accommodation ?
You need to explain in the listing what the price of electricity is, how it is metered and how many KwH (or money) is included in the renting price. Then after the stay has finished you can charge guests via Resolution Centre. (but if they do not pay, it is not easy to get the money, as there is no actual deposit...)
Is it possible to let guests buy there electricity themself during the stay (by the prepaid system ? )