My friend was taken to tutorial and a fresh account after launching the app today. Any help recovering her account?

So today at 330 we were playing on a break during work and everything was fine, then at 5 when we got off we went to do another match and upon launching the app she was back in the tutorial, she went through it to get to the main screen and went to settings to reconnect her Facebook but got a notification saying "this account is linked to another game would you like to link it to this game" which we said no to because we didn't want to overwrite her other account.

It still exists because she's still in my clan and it's pretty frustrating because it's a level 12 account and has all her legendary trophies and season bests and well everything card levels etc.

What else can we do? Logging into Game Center again didn't work neither than deleting and re downloading the app.

Any help would be greatly appreciated, thank you!