Fortnite Pocket Manager allows you to view your locker and purchase items anywhere, but there is a catch. You have to give the website your Epic Games account. That should have been a red flag from the get go. Now, Epic Games is banning accounts that use these websites.
If you have an account, delete it and delete the app.
Fortnite Pocket Manager: Stay Away From the Third-Party Website
Simply enjoy Season 10 of Fortnite and stay away from third-party websites unless you want your account banned.