i got an ipod 5th gen. off of craiglist. before i relized that i needed id and password the person chaged his number. now im stuck what can i do please help

im needing help. i have a situation i bought a ipod touch 5th generation off of craigslist. i hadnt mess with it for a week because i was leaving town when i got back i had relized that the ipod was locked. so i tryed to contact the person i bought it from and the phone was no longer in service. i met him at the store by my house so i have no way in contacting the person. i went as far as to go back on cralgslist to find his post and found that he deleted it. now my question is i have this ipod i don't know what to do. can you help me to get in to it so i can use it? my granddaughter is very unhappy. i would hate to have to just toss it out.