Cognizant — joining date

I have attended interview on 24th november 2018 in bangalore at manyatha tech park. After hr round, i got offer and got a mail to fill pre-joining formalities on december 11th 2018, and they have approved my pan card on 15th december 2018. But till now didn't get joining date. So can you please tell me that when will i get joining date.
Name : triveni guntimadugu