Whether your employer is a public or private sector undertaking? Whether any contract was entered into between you and your employer at the time of giving loan regarding the deduction of loan installments from the subsistence allowance? The answers to the above questions are germane for rendering any advice.

in case you are a bank employee there must be provisions relating to Payment of subsistence allowance and the Deductions permissible as per the Bipartite settlement entered into by the bank with employees .

generally there is a clause that compulsory deductions like income tax and repayment of loans and advances granted by the Bank should be recovered from the subsistence allowance payable to the suspended employee though such allowances may not be treated as part of salary. Further, from the subsistence allowance, it will be in order to effect other optional deductions like insurance premia, dues to co-operative credit societies etc., unless this is objected to by the concerned employee. Provident Fund Contributions should not however, be deducted from the Subsistence allowance.

in case there is such a provision you have no case to complain about alleged deductions

You will be governed by agreement you have with your employer/rules made and accepted by you.