Telemarketing - does it work

"Ring ring ring..............  Ring ring ring......................"

I just got into the door, and heard my house phone ring.  I picked up the phone, guess what......

"Good afternoon, madam, how are you?"
"I am good, thanks"
"I am calling to offer you the service to block all telemarketing calls.  Once you register with us, the telemarketers cannot call your house phone.  It is illegal that they contact you once you register with us..,... "

All sounds good.............. 
The caller keep talking, then he asked for my name, confirm my address and then ...  mobile phone number....

Ok, do you see what is missing here?  There was no mention of cost by the caller...  and.. why would I give my mobile number to a stranger?

"How much will that cost me?
"..  Oh.... that is a very good question.  Just let me explain... once you register with us, it will block all telemarketing calls, charity etc etc and you will only receive calls from your friends and relatives.."

"Ok...  how much will that cost me?
Knowing he can't get away with it....  "that will only costs you $49.95 and it will block all telelmarketing calls..... "

Sigh......... 
- He has just wasted my and his time;
- It is real hard work for telemarketers.  He must have made so many calls and getting impatient;
- By the way... I still don't know which company he calls from;

Typical response to telemarketing calls is "No thanks, I am not interested".  Worst of all, probably just hang up the phone.
So, does telemarketing really work?
With so many scam out there, I will suggest not to give out your details, and be careful before engaging the service, when we have no idea of the caller.

Even if I remember the company, we don't even know whether he actually comes from the company he claims.

So.... think twice before engaging the service.