I have found out it is optus,I have definate proof someone i know works for them. It is definately optus so if your with them change to another, i am going to change!!! Every one unite stand up to them and change providers they deserve it...

Yes, i have also received missed calls from this number.

I am unsure of who it may be, but the consensus seems to be that it may be optus.

Thank you for your tips.

Just recieved another call from this number and it woke me up again, two days in a row now.... tried to call back but number busy. this is BS!

I was getting call from (02) 8087 3088 until yesterday and today it is (02) 8083 0100.It is obviously spamming or scamming. I am not with optus or telstra so whoever it is is just cold calling to scam people.
It is a real pain in the arse and they should be shut down

this c**t keeps calling me to

I believe its from Optus checking up on your rate plan.  Have you recently changed to Optus?