I've just signed both my daughters in for the first time, as the links were sent to my (the parent) email. So, it logged them both in with my email and then asked me if I wanted to link the student accounts. I did not realize at the time we could create a parent account separately, so I clicked for the accounts to be linked.

Now, it's showing both of my daughter's classes under just one of their names, even listing her name under her sisters class enrollee lists. 

How do I unlink the student accounts?