Optus My Account Service Express Billing Application.Now you can monitor your iPhone call and data usage using the official Optus My Account Service Express billing application. This billing application allows Optus Mobile Postpaid Customers toView your unbilled usage for eligible iPhone plansView your last 4 bills Pay your bill by credit card Optus Mobile Prepaid customers can View your prepaid balanceView up to 100 most recent prepaid transactionsRecharge your prepaid account via credit card or voucherThe application is free but download charges do apply for downloading from the Apple App Store. When using this application on the Optus network data usage is not charged (when using the service overseas, international roaming charges will apply).To use this application you must have a My Account user name and password. You can register for a user name and password by going to My Account at www.Optus.com.au/myoptusaccount. My Account also contains useful information and further billing details.Optus iPhone Support Helpline: 133 713Please note that account information and usage can be delayed for up to 24 hours (48 hours for newly connected customers).Credit card payments are encrypted & secured by Entrust.