Hi, I received a "missed call" from +614011 (optus prefix of 0401 I am guessing?)...but that was it. 04011. Where are the remaining numbers? I have heard of this either being an overseas scam call centre spoofing their number badly to get around call blocking, or some agency such as a debt collector hiding their number for I guess same reasons. I have no debt and nothing to do with debt collectors, tax or police etc?
I also find it odd that this is the only call I have received of this nature, as I never give out the number or use it online or reigstration etc etc.
It is probably as you suggest, a spoofed Caller ID or a badly formed notification to your device of the caller ID so it's come through corrupt.
If it's a single occurrence, I wouldn't be too concerned.