My Company not following Indian income tax slabs and taking 10% income tax direct from monthly salary.

My Company not following income tax slabs and taking 10% income tax direct from monthly salary. They said there are two ways of tax deduction one using tax slabs and they are deducting common tax of 10% monthly from all employees. They said this is how our CA is doing.

My salary 9.6 LPA, according to new tax regime I should be liable to pay ₹2816 as TDS.

But Company deducted: TDS = 8k Professional tax = 200

I want to know is it illegal or Okay ? What should I do or ask for ? They will provide me document structure how they deducted tax.