Icici po programme opq test

Hello mam

I cleared my aptitude test for ICICI PO and received a mail.In that it was mentioned that i should take a OPQ test within two days after receiving the mail, in order to participate in GD/Interview .from the time i received the mail i am trying to take the test but as i enter my username and password it displays something like

Attention: Your login details are not recognised. Please contact your assessment administrator.

Its already the second day.What should i do now.please do reply.