Did not mention any rules or agreement that if u do not achieve target we will hold your salary?

Sir this Anand from Bangalore Karnataka.I am working in Pvt Ltd company .From 3 last monts I am working this company They paid two month salary but 3rd month salary they pay me half salary .while asking them they told you are not achieved your targets from 3 months so we release 3rd month salary half. But in my job offered letter they did not mention any rules or agreement that if u not achieve target we will hold your salary, Now they holding my half salary .Regarding this whom should I complaint about this issue please guide me.

The company is behaving badly and cheaply.
What is your salary structure?
Basic + incentive or only salary?
Have they cut salary or paid less incentive?
Pl check with them.
If they have cut your salary pl write an application to the HOD and top boss asking for clarification.Look around for another job on priority.