Welcome to the AGL Community!
This sounds very frustrating. We'd like to see what we can do to help here, but in order to do so I'll need to ask you to send me a very quick private message with your AGL account number and email address first.
I got a call on the same day from AGL Escalations team as I had posted this here. We were told that this was an AGL mistake and that we had been overcharged. We were told that we will get an updated bill.
On Wednesday, we got an updated bill which was incorrect again with an absolutely different issue! initially there was issue with my cooking gas meter. AGL fixed that and overcharged my hot water gas readings which were correct from the beginning and there was no need to update the same!
On Friday, we had a word with escalations team again and now we are waiting for "ANOTHER" updated bill. Hopefully this time AGL gets the numbers right.
It's unfortunate that the time and efforts we have spent getting this fixed is maybe more than the the worth of my usual monthly bill.