Broken cell phone

I purchased a Mobicel Sonic on the 5/9/2015, due to moving of my residence I lost the paper work and box, The phone is now broken, I have spoken to the staff at Mobicel who are extremely helpful and they did inform me that they can book the phone in for repairs, However Vernon from Ackerman's does not want to accept the phone, this phone was purchased on my Ackerman's account and the store say they don't keep records of the phones they sell. I even phoned Ackerman's head office and spoke to a manager by the name of Candice but still no help.