I returned a call from (02) 8484 1317 but the voicemail didn't mention the company name

It is for the MS Swim held every year

https://www.msswimathon.com.au/

Caller: I do not know

While I do not know who called me, I did however have a number and called the number but like the others on here. I reached a VM and my call ended.
When this number called me and I didn’t answer. The caller could have left a message but didn’t.
This caller displayed all the hallmarks of a typical nuisance caller and as such I have taken appropriate action to ensure I will not be bothered by them again.

I did the same and it went straight to their voicemail. They didn't leave me a voicemail.

I called back the number (02) 8484 1317 and reached vm that did not mention the company name