Beware of this consultancies:

1.Mastech Sys
2.Syntel
3.Computer People Inc.
4.Capricon
5.American MegaTrend Inc.
6.CBS
7.Intelligroup (Edison - New Jersey)
8.Cybertech (Chicago - Ilinnois)
9.Systech (Gelndale - Calif.)
10.IntecNew Jersey. Now it is named as Compuflex.
11.Indotronixs or Indotronics?
12.Capricorn Systems Inc , Atlanta
13.Frontier Systems ***(Highly Black Listed)
14.C G VAK(Coimbatore)

 Source: http://www.desihotmasala.com/2008/01/black-listed-companies-be-aware.html