[Resolved]  Byju's — lost all the data

My tab stopped working today so i tried to repair it and in that process i rebooted the software. So i lost all my memory and all apps. Later i installed the byju's app from sd card. The app is asking for a pin for activating the app. I checked the whole box given to me but i can't find the password. So can you please help me. My studies stopped because of this.