Lovely Professional University - Forcefull Salary Security and Very Low Interest

The university has a policy of keeping original documents when I joined LPU. But after * year they forcefully started cutting salary saying now they have changed the policy and will keep * months salary as security. Whenever the salary increases the will cut two months increment and add it to security. The security kept on increasing. I asked them this is unlawful but they did not returned my money.
In **** they themselves returned the security money.
In **** they gave very low * percent simple interest on the security money. The interest for **-** years is only **% of total security money kept with them.Moreover the interest I got is taxable.
LPU used my money for **-** years and during this period If would have invested my money in PPF it would have grown ***%-***% and it would have been tax free.