Just got one,very annoying!

Same problem - many calls from (02) 9007 5100 and they hang up when answered. Can this be stopped and does anyone know how to have it stopped?  Is there any costs associated with receiving these calls??

Had a few calls from these guys. sick of it as they always call at the wrong time (ie when i am sleeping!).

hey i just got a call from this number? whats the go? i dont answer numbers i dont no. does anyone no what it about?

Ive had calls from this number, as Im on prepaid telstra account holder, just once,  I answered the call and heard a couple musical notes, then a "drop out" tone........ I then checked my prepaid credit account to find I had been charged over $6.00 for this call, How they do it? I have no idea, its very annoying and frustrating, not to mention costly.  The next move is to change my number, again being costly and who is to say that this same number wont find my new number too, and Im left in the same position.

They call several times a week then hang up when answered. The voicemail message is unclear