You are not supposed to work on off days/holidays/leave……………..
The demand of managers to work on off days/holidays/leave is a transgression.
It is a wrong notion that IT Company won’t have any leave register (record).
The IT/ITeS companies might have been granted approval to have self certified records in electronic/digital form. The forms and formats might be same as for hard copies as prescribed in enactments applicable to the establishment e.g; (Name of your state) Shops and Commercial Establishments Act………………………
IT/ITeS companies are also covered by enactments applicable to commercial establishments…………….and are not free rule of law.
You must be having leave record/leave submitted by you, approval given to you with date, reports submitted by you with date……………………as date gets automatically affixed on emails.
You have the option to request in writing to amend balance leave record and treat your leave cancelled or claim OT (if you are not in Exempt category) and compensatory off as described in
(Name of your state) Shops and Commercial Establishments, National Holidays Act as applicable in your state……………………….
Claim of OT should be lodged in reasonable time……………………………..Employer should pay OT along with wages on due date of payment of wages.
The managers/HR/employer may claim that you were not asked to work on these dates and you submitted on your own and voluntarily (and may add that since you did not complete work in scheduled work hours and delayed it)…………………………..
Therefore it shall be appropriate to obtain proof (audio/visual/written) of work being assigned on off day/leave/EL/holiday etc……………………
Since you are affected you have to act. Try to sort out amicably.