Please let Energy On know about your intention to move out of your property, and the date you will be vacating, which can be done by submitting a ticket here.
After you have moved out, you will receive your final invoice from Energy On around the same time you would normally receive your monthly/bi-monthly/quarterly invoice.
Once you have received your final invoice, you will not receive any more invoices. After paying this invoice, your account will be fully closed, and you will not receive any further communication from Energy On.