As long as you receive your basic pay then it is in order. Since your variable salary is based on target you will considered for a varible salary according to the target achieved by you as per the terms and conditions of your appointment order.
However they cannot stop your basic salary on any account unless there is a clause to that effect in the terms and conditions of your apppointment letter that the basic pay depend on achieving the target etc.
14th May 2013 From India, Madras
Generally, wherever basic salary as fixed component and variable component based on achievement of target, the basic salary is paid irrespective of achievement of any target level and the variable component depends on the percentage of target level achieved. However, you have to read the letter of appointment to know as to whether any conditions are set even for basic salary. Peruse your terms and conditions of appointment minutely and understand. If you feel that you are entitled to basic salary and the employer refuses to pay, you may approach the Labour Commissioner of the State for redressal.
Best of luck.
14th May 2013 From India, Mumbai