There are two main ways to contact us by email - one for NetBank If you're not a Commonwealth Bank customer yet, you can find answers on our Support Community. You can also phone us or visit your nearest branch. Find answers to your Commonwealth Bank questions here - includes popular topics, top 5 Contact CommBank You can also reach us by phone or email. Commonwealth Bank FAQs, phone and email contact information and information on how to give feedback. Log on to NetBank and other · Business Banking · CommInsure.