An Australian Company Number (ACN) is a unique nine-digit number that is assigned when a company is registered. Every company in Australia is issued with an ACN and it must be displayed on all company documents.
You can use the ASIC Professional Registers Search to check whether the ACN you have for a company is registered or licensed with ASIC to perform a service. Be sure to check the details of what they are licensed to do, such as provide advice or offer investments.