Seems like you could present this evidence to the police for an identity theft charge against the "wrong person." Or you could threaten to do so, and perhaps regain your property.

Except, read the comment again - Josh changed the account so that it referenced the other persons phone number. They did not steal his phone, and it could be framed that he gave them the account.

Accusing somebody of theft? Perhaps the police would side with the non-felon..