I have had several calls from this number and do not know it, last time I answered it there was no one there. I have now blocked it.

Rang for one ring then stopped, a return call gives an engaged tone after a longish wait. 6May2008, 1445.

Been rung 5 times this week by that number. Normally around 2.30pm in the arvo and again around 4.30pm.

I've been called 5 times by this number and there is no response on the other end, and am also a carlton member.
The club has clearly sold member details to Origin...

Two calls today alone, 17 May 2008.  Answer the phone, kind of a delay, then the phone goes to busy signal.

The Origin website does not list this number or anything with the same prefix in the business divisions listing.

http://www.originenergy.com.au/1708/Business-divisions-and-locations

If the number is Origin it is likely to be an outsourced marketing call centre.