Someone steals your phone. You can sue that someone for the value of lost property if caught or if the police recover money.

If he sells down the line. Police will follow the chain and if the property is found it will be taken and it will be used in trial and recovered back to you.

The people who bought the used phones may lose them. If they do they can sue the store. If the store hasn't sold them they will lose them and can sue the orginal thief.