^^
expatlondon,
You're going to need to call NMSC again and ask them to provide your daughter with an access code and temporary password to enter her information on the online web site.
Web Site:
https://osa.nationalmerit.org
At some point, the school administration needs to engage in the process because they are required to do a few things to help your daughter advance from semifinalist to finalist. You should ask NMSQ for advice on how to handle a situation where the administrators are unresponsive to requests for assistance.