You can update your email address and phone number in your Member Zone.

Click the Profile icon in the top right of Member Zone
Click My account
Under Contact Information, click on the contact details you wish to change
You will be given the option to update the details that are specific to Member Zone or your Health plan
Click the chevron to proceed
Enter a new number or email and click Next
Enter the code that was sent to your email address and click Next
Enter the code that was sent to your mobile and click Next

Confirmation will come up to say that your new details have been verified.

Health plan personal details