Thanks for your post!
We've recently identified a section of customers who have not had their discounts applied correectly to their latest bill. We've rectified the accounts affected and it sounds as though you've recieved a new bill as a result! We'll ask you to pay the bill with the latest due date of the two disregard the other.
Welcome to the AGL Community!
It sounds like you may have received a revised bill, there can be a number of reasons why this might be the case for you. We'll need to check your account and the notes from our billing team to see why, please Contact Us so we can check this with you.