Your guide to making complaints to Commonwealth Bank Australia.
http://www.commbank.com.au/contact-us/compliments-complaints/default.aspx
For direct contact CBA advises you to contact General Enquiries – Ph 13 22 21
If you are not satisfied with the outcome, they further advise you to contact Customer Relations – Ph 1800 805 605
https://www1.commbank.com.au/eforms/yourfeedback/yourfeedback.aspx