Hi there and welcome
you will need to reset the device. It will wipe all data and return it to new, but this you cannot avoid sorry.
Can you power off the unit
Then hold the power button and volume up until you reach a menu.
From the menu, choose using the volume keys, wipe Data.
Use power to select, let this complete and when it has, the device will be as new, and you can set it up again.
Let me know how you go please.