Do click here to go to your payment page.
If you already have a bank account added and verified in your ShopBack account, you may add another one by clicking on the box with the '+ Add a bank' sign next to your already added bank account. The box is as per screenshot below:
For detailed steps in adding your payment details, do refer here!
Alternatively, you can also add your Petron Miles card so that you can change your Cashback for Miles points! Just click on the Points Redemption tab at your payment page as per below: