I have had dozens of messages left on my answering machine with this 1300 number and a reference number but no info on who or why they are calling. The return phone number is not associated with any company in any online source so does not lend any credibility to them. Caller accent is obviously from Philippines.
Calls appeared to me as an attempt to steal identification through some sort of telephone phishing scam. Very dubious and persistent if not harassing phone messages with no info on who they are and why they are calling.
I eventually returned the call to find out the source and to stop the calls. Turned out to be a collection agency (Baycorp) attempting to find someone with the same last name as me. Since I have no association with Baycorp (or the person they were trying to find) I believe they may have broken the terms of the Do Not Call Register Act.