Gst provisional id & password from sales tax website

I tried to get the provisional id & password for GST enrolment by logging into the firm's account at mahavat.gov website but there is no 'flaash message' that is supposed to appear that will give me the id & password. The firm is based in mumbai & is only registered under mvat. I have tried to log in with different browsers & different systems also but cannot get the id & password. Is there any other way to get the id & password?