Is somebody in my fortnite account?

Every time i change into fortnite again my skin changes and none of my friends has this account… Please help me what can i do about it and suddenly i have 50 robux even though i had 50

1.) Learn German

2.) "Suddenly I have 50 robux even though I had 50?"

3.) Change your password.

Yes, I have your account

Very helpful

I can speak German and I mistyped 2. Number 1 thanks I try