Missrepresentation of product

I received a call from a call centre agent selling a special of 1Gig data with a Samsung Tab 3 lite device. I received the package yesterday and opened it ********ly coz it came in Vodacom packaging. only when I looked at the gadget I realised that it is a Vodacom tab 3G and not the tab 3 lite they promised. I remember she said if I open the package it won't be taken back and that would be really unfair coz she misrepresented herself on the device she was supposed to send. I have been phoning around to get hold of their offices to query this but cannot come right. The Vodacom shops refer me to a call centre number which I can only call from a Vodacom number and since I am not get through. this is frustrating and I need to return the package so I can have the correct devise sent back to me. I just need them to call me back since I can't call them and this has to be done within 7 days so I can exercise my cooling off period rights.