The caller with the number +61399766901 is likely associated with Lumo Energy, a company that provides energy services, as indicated by the caller type mentioned in the comments. The purpose of the call seems to be related to account issues, as one of the comments mentions a call regarding issues with their account. The fact that no voicemail was left and the caller is from a call centre suggests that the caller may be trying to reach out to customers regarding their accounts or services. Overall, the caller appears to be a legitimate company trying to contact customers, but the lack of information left on voicemails has led to some uncertainty and speculation about the caller's identity and purpose.
Looks like a call center, see a bunch of simular numbers reported with the same start but diff endings, all seemin to be from Lumo Energy. No idear whos behind it tho
They rang about my acount, no voicemail left so I called back