I got call from this number many times but no one on other side and not even leaving any message.

I got 2 missed calls but no message in voice. I hate when they dont leave a message, how would i know its not a spam

per job board post via google search:
Dec 6, 2011 – Nancy Young. Technical Recruiter. Phone: 908-765-0004 ext 328. Phone II: 908-765-0005 ext 328.
22nd Century Technologies, Inc.,(TSCTI)

They are an awful recruiting/staffing company. I worked for them on a state contract for 18 months, they never return phone calls or emails. The pay is good, but don't expect them to care one ounce about you. They are an Indian based company (which there is nothing wrong with) and make their employees use American sounding names (which is deceptive) and no one there understands English very well. My suggestion is stay away from them, you can get the same job from much better reputal companies.

got a call from a "Sandy", stated she or he had a job opportunity for me.  Left message and was a male caller - they could've at least picked "Bob" or something instead of Sandy.  Caller also had an accent.