If your subdivision is strata there should be an OC.
So you may well have an OC, it’s just that in Victoria, for horizontal type stratas with no common property and with building insurance passed to lot owners, the OC can be effectively dormant if it chooses. For these types of OCs there are usually no regular cost issues.
If you’d like to find out if an OC exists, go to Landata:
https://www.landata.vic.gov.au/
Just typing in your address with give the information about if a Plan of Subdivision and an OC exist.
If there is an OC, get with other owners and have a meeting if you choose.
The OC Act still applies.