Unprofessional Behaviour - HR

No one can be more unprofessional than TCS HR. I am on notice period. And I need that HR acceptance of my resignation and the last working day, but the HR is least bothered to reply me. However, my manager has told me that my last working day is 11th of February and he has also given me a written confirmation, but thought of getting it from HR, but HR is least bothered to respond.