Locked Iphone Sold

I have ordered a refurbished IPhone5 from Groupon, I have not received any tracking no, and after 4 weeks and numerous phone calls and long waiting on the call center, the phone arrived. when I switched it on it was still activated and locked by the previous user. I have immediately contacted Groupon and they have assured me that the phone would be replaced, how ever I have to place a new order and make another payment for the new order, I then have to return the faulty phone to Groupon. It is now more than a week since I have logged the return. When I have phoned to check on the progress, I was informed that they have none of this on their system.