Airtel — Related block payment account

I am using airtel money a/c with [protected], but i forgot my Mpin now my a/c is blocked i tried to call 400 and do as per call but i am getting message "MPIN Reset window is closed." i am not able to reset my Mpin and i have approx rs 300 in my a/c. would you please do the needfull.
but still i didn't received any message from airtel.