What a person should do if an employee is harassed by all managers and do not get HRs support

Percentage of getting everything backfired at you is more because all hrs and account managers support each other.
Start looking for a job outside...

First of all get everything in written. Let’s saying not allowing leaves, etc. Then keep looping the people in that mail trail. This much is enough for the manager to stay in his aukaat.

Drop mail to hr about it if he doesn’t take any action report to his manager still no response msg to upper management

Please explain about the harassment part... People have different understanding about that.. You may be feeling it is harassment but for the it would be normal thing

Account managers and HRs support each other as both sides are part of TCS since long.Are you a lateral who has recently joined project? Get immediate release.