I logged out of iiser registration now i can't login back . there is no registration/ login option . There is only registration available . now how can i complete the registration ?
I'd suggest you to check if there's any link in the email if at all they sent to you. Otherwise you can register again. It won't be a problem.
Also, you can try contacting them with the helpline no. or the email id they give away at the bottom of the page in which you register.
If you would be able to find option sign up so do it. Otherwise do your registration again.