called six times in three days

Can someone explain how these low lives are making a $ out of this process; i.e. call. hang up when answered, no message left and if attempt to call number, it is either disconnected or out of service. (Oh yeah). There must be millions of these calls being made world wide indirectly, costing business and private individuals valuable time and money. What can be done to stop these serial pests? Blocking numbers doesn't work, they simply use another that other spurious organizations sell or rent on the web.
A concerted effort needs to be made by Telcos to stamp out this practice.

Every day they call once you block them they just use different line.
I’m on the do not call registry but that doesn’t stop them

Nuisance Constant caller, Hangs up when answered.

nuisance call ; block the number

Sick and tired of them calling. Hang up when I answer. Public nuisances. I can't seem to block them.

Called lots of time and hung up immediately. Very annoying

sick of calls from this number

Three times in two days. First call missed. Today 2 calls, 30 mins apart about Solar Rebate scheme. With the first caller I replied that I had solar panels and to not call again. Half an hour later another call -- I told them my number was on the 'Do not call' register and they were breaking the law. Hung up as soon as I mentioned this.

8 calls in 2 days..

BLOCK THIS NUMBER. Hey are so annoying - I answer and they keep hanging up!!

They've been called me for weeks. Usually they just hang up when I answer. Last time I answered they tried to tell me about a government scheme but refused to give me any details about it, I yelled at her and told her to stop calling this number. I've blocked the number but they still call and I get messages saying I have a missed call from this number

Called twice a day for past few days. I never answer.

I tried to get some information from these people but they just hung up.

Phoned four times in one day. Serial pests!

black

Called 6 times over 2 day period. Blocked

Laughed when I said block me. Do not answer.

This number calls me almost daily and of course never leave a message. I tried calling the number but it will not connect. Finally I answered the call at 8pm. A female with an Indian accent wanted to talk to me about installing solar power with a $3K discount. Told her never to call my number again. Clearly this is an overseas call centre hunting out the gullible. I hope no one gets caught up in it.

I have had the same thing. I've told them each time I am not interested and to remove my phone number. They wont let up!
Lovely feature of the iphone is the Block This Caller, I have used it on this number. Sooooo annoying!