@Jo160
Hi Jo, a security deposit will not protect you against guest excesses....you have to protect yourself. And as mentioned you cannot alter the terms of an existing reservation, you can add a security deposit to future bookings but not to existing ones
As far as your internet is concerned, are you offering a cellular service, one linked to your mobile phone? If you are, I would suggest you have a 'pre-pay' on hand with 3 Gb of data on it. It is a seperate service from your personal phone service, You can get these from any supplier for less that $20 and if the guest requires internet access give them this and when the 3Gb runs out they can recharge it but, the recharge is up to them. You are doing the right thing by the guest and you are not leaving yourself open to abuse! Contact any service provider and they will give you details!
If you you have a landline based service you should be seeking out a better provider. I pay $60au per month for unlimited high speed broadband and a free vOip home phone service. Provided it's legal they can use as much as they like, it has no effect on me. I just give them the wifi name and password, I never get hit with a bill.
As to your power, put your major draw appliances on pnuematic timers. They can be set from 5 minutes to 1 hour and after the time has elapsed they have to push the pnuematic switch to restart the appliance.
Guests can be wasteful Jo, they consider they are paying for it, they will use it. But unfortunately there is not a mechanism which will allow you to charge for these excesses through Airbnb!
Cheers.....Rob