Yet more attempts to give technology answers to a people problem!
Correct answer:
Tell the person who messed with your phone to sort it, now, at no expense to you, and in the meantime you're borrowing their phone. Then it's their problem, not yours, to find out how to do it.
OK OK ... you're going to tell me it was a small child wot done it. There must have been someone responsible for the child, so the same applies to them.