Just checked my account statement this morning, realized my NBN extra talk bundle ($20) has been charged on both 3rd Feb 2020 (deducted from my account on 5th Feb 2020) and 7th Feb 2020. I am wondering what is happening regarding the small time interval between these 2 charges.
The $20 charge is the payment for your homephone add-on which is the Extra-talk bundle. Since you upgraded your plan, any unused portion from your previous package will be used as a credit on your new bill.
It is already posted on your account and the only amount you need to settle is $12.07 which covers the period from 2020-02-10 to 2020-03-09.
Hope this answers your query.
Feel free to let us know should you require further assistance.