Purchased an Iphone 5 on Kijiji. Still Locked to Telus HELP

Bought a Iphone 5 off of Kijiji, Owner said it was unlocked, and he was getting rid of it because he was moving away, went to set it up with Rogers Canada (my Carrier) and they made it aware that it is not unlocked. I contacted Telus several times, they said that they can not unlock the phone because i am not the original owner of the phone. Have tried websites that unlock phones, there is no Telus unlock. It has been over 2 months without a phone now. How can i get my phone unlocked from telus to put on Rogers.