Vodacom Upgrade - Wrong Phone

<p>I upgraded my Vodacom contract yesterday, when i realized it was the wrong phone i called their upgrades department immediatly. They informed me i could return the phone the next day for the correct phone. Vodashop Vodaworld is now refusing to exchange the phone for the correct one saying the information from their upgrades department was incorrect. I was asked if i recieved a form which states the phone i was given and whether or not the box was opened at the store. I did not recieve the form nor was the box opened to check it. I was told i shouldn't have inserted a sim card in the phone or used it. I had to use the phone to call them to inform of the error because my old phone went in for reparis. So basically im stuck with this phone for 24 months. Please can someone assist me</p>