Thanks for reaching out@Jemmapacker, have you registered the service for Optus.com.au/myaccount?
Log into My Account
Click on the Dashboard tab
Make sure the correct account is selected (if multiple accounts)
To switch between accounts, click on the page icon under Request payment extension
Scroll down to see Your Bills and click View Details
Navigate to Current Bill Settings (on the right hand side) and click Edit delivery method
Select Online and click change your notification settings to set a preference for email or SMS bill notifications
Click Save to confirm
If you run into any issues, give us a shout!