Overtime Wages rules in IT companies

I have some doubts regarding the office timings that should be followed by IT companies in chennai(TamilNadu). As far as I knew, according to factory act 1948, an employer should not ask an employee to work more than 8-10 hours a day or 48 hours a week. But in my company I was asked to work for more than 10 hours a day for 6 days in a week and then there are no overtime wages. When I enquired them about this, they said that IT companies won't pay overtime wages.