Q: how i can delete the jilbroken ?? and get my data back

Hey after all just let me to make this clear to you I'm not expert in the apples devices from too couples days I want to play with my iphone... But there were a problem with the apple store so I went to store near from my home... He told me to download something call " jilbroken " !!

As I said before I'm not expert in the apples devices so I approved! But then my iphone unlocked!! With an ID apple and now my iphone completely crashes and dosen't  open

I want to delete this thing uh I'm so frustrating now I want my data back from the backup he took it from my device is that possible? And if I buy new iphone can he put the old back up again?

Or is there any way to delete it?

Thank you