iphone unlock

Today I was suddenly asked by a person to unlock his phone, he tell me that, he forgot his phone password. so

I started doing as he said and asked is it your phone ? he said yes it is my phone. I believed him and reset the phone. Now when I asked for more information from him during the reopening this Iphone he could not give me any apple id that match with his phone, he said I am going to home and bringing all the papers but since then there is no trace of him. What should I do at this moment ?