Clicks refuses to take back Device

On the 20th of Dec i Purchased a UID device at clicks Lemon Tree, today i went to see a gyne as my appointment was scheduled, upon examination he discovered that i cannot use UID because of my medical history and advise that i return it back and purchase something else. when i went back to the store they refused to take back the Item and yet i have the receipt and the device is still sealed in its original box. now tell me how is that possible that i cannot return what i bought when its still in its original state, i spent over R3000 to buy the device and now your telling me stories, am fuming right now

Name: Merilyn Mulisha card no ***