DONT NO WHO THEY WONT TALK TO ME WHEN I ANSWER

Got two calls from these jokers at 310-855-8939; then they just hang up!

My message here mirrors everyone above.  The numbers that keep calling from TTI are: (310) 855-8939, 9421, 9489, 9140, 9274, 7332...They show up on my caller ID.  The callers (telemarketers?) are always rude and never allow me to ask for a supervisor or to tell them to remove me from their calling list.  I have called back every single number with no success in reaching a person.  The number are always busy or ring off the hook.
I am on the national do not call list and somehow they are still calling me.  I am totally annoyed and would like to find a way to solve this.  These people need to make a living, I understand that...but the way they conduct themselves and their business is out of control and I'd like to see them shut down.
What the heck is TTI anyway??

TTI has been calling me for months from at least 12 or more different numbers.  Spoke to a person one time, and they hung up on me after I told them that I had no interest in whatever they were selling... and NOT to call back  I cannot get through to ANY numbers for them, to ask to get taken off their list.  So far as I am concerned, they are the lowest of the low .....a complete nuisance, and seemingly unlegal in their methods of harrassment. Cannot believe that their methods of incessant phone calling, sells ANYTHING to anybody.

Some dumb man called for John and then could decide if he called for John or Jim. I corrected his dumb self. He said oh and hesitated for a couple of seconds then hung up. He calims he is from Trade Tech. Yeah right, sure buddy. Liar!

Call received from 310-855-8939 after 5pm on a Friday, my daughter answered, a lady asked for my husband's name, my daughter said that he is away, she asked for a number to reach him and my daughter, of course, said she couldn't give that number.  The lady did not volunteer her name, where she was calling from or why, and she didn't ask to leave a message.  My research indicates that this phone number corresponds with the name "BISORAJ OOPADHYAYA," listed in Los Angeles, CA.

Have received a call with no messages at a random time every one to two days since the 9th of February (today is Feb. 24). The number is unavailable.

Is becoming a real problem.