Plarium may be able to help.

Your friend will need to contact Support.

At the top of the login page in the browser version there is a Community tab, click on this then on Support.

This takes you to the faq. I am guessing "Linking and restoring your account" won't be useful so go for "Ask a question" but read "Recommendations for contacting support" first because this is not a simple problem.

Your friend will have to do this herself as Plarium will require confidential information.