recevied this call 21 times today.. rang optus to abuse them and found out its not even them its some stalker psycho.. on the phone with optus now they're checking it out.

This appears to be a recorded call from Optus and rings up regarding your plan saying it will take "3 minutes".

Optus

receives this call daily while at work and when i go to ring it back its engaged

I answer they hang up.

It's Optus calling you with questions about your current plan and to do a survey.