Yes today I got 2 calls and this time I decided to answer but they always hang up, its like they want to check do you still own this phone or are they using your number for malicious purposes. (Have now blocked)

I have received numerous calls from this number, they seem to do it in 3 day intervals. I had a call every day from 28/1, 29/1 & 30/1 then they started again this week. 3 calls so far. I answered the first time they called and they hung up. Now I just let it go to voice message but they never leave a message.

constant calling, never leave a message and when you do answer they hang up straight away!!!!
have also blocked this number

I have had 5 or 6 calls from this number. I don't know anyone in WA and don't answer unknown callers.

I've had this number call me 4 times in 3 days. I never answer unknown numbers as if it's important they can leave a message. Been hearing it's an Optus spammer, which would make sense as I am an Optus customer.

Been getting calls every week for the past couple of weeks, I never answer.

Got a call from these people, I didn't answer thanks to the above comments. No message left either

I've been getting these calls the last couple of days - went to answer and they hung up just like the other comments....
Blocking the number on my phone. So rude and no way to treat your customers!!

Have been getting a call from this number for the past couple of days. I answered the first time and they hung up. Surprise! I'm an Optus customer!!!

I have the same experiences with others receiver. Please D'ONT do the stupid thing like that. Telephone means of communication and should not use for any other purposes. You will be abused should the number came up again. Dump.

Had a missed call (I never answer unknown numbers, they can just leave a voicemail). They didn't leave a voicemail, therefore I didn't call back. Someone mentioned Optus spammers, and I am an Optus customer so that makes sense.

I had a call which I answered and they hung up. I rang them back to get an automated voicemail from NTC Voice Solutions advising you to call them on 1800 283 174. Have rung this number back, they're a telemarketer for Optus. Their website is: http://www.ntcvoice.com.au/about-us.aspx

Most likely you received their call if you are a Optus customer.

I got a call on the same day around 13:01pm. I answered, they terminated the call and I rang them back to get the NTC Voice Solutions unmanned mailbox, please call 1800 283 174. Am disgusted.

They hang up as you answer the phone. Upon returning the call, the announcement says you have called an unmanned mailbox, and that you should call NTC Voice Solutions on 1800 something or other. It's a despicably cheap way of cold-calling.