Well, there’s two questions here, isn’t there.
You’ve lost data. Back it up next time. There’s really no excuse with a modern phone irrespective of handset choice, I was syncing my first phone with Outlook back at the turn of the millennium.
Your handset has “died”. You’re not clear as to exactly how (and an errant app doesn’t generally cause hardware failure) and don’t give any information as to what phone or what app we’re talking about, but irrespective of contract or PAYG you should have a two year EU warranty on electrical goods.