It could be possible that the user Id and password you got was for Trade Now and NOT for InstaTrade.
As of now InstaTrade is avaliable only for franchises and not for retailers..It will be soon made avaliable to normal traders too. The user ID and password are different for all three- TradeNow, InstaTrade and PowerTrade.
Moreover if possible you assign another person as your nominee, ofcourse who has a PAN card..
Contact RM or the person who opened your account..I think this matter can be solved..
Dont panic