returning of the product that i am not happy with

hi I bought a mobile phone on the 27/06/2015 model HI M1010 DS Black I returned it back on the 02/07/2015 and on the *** Magdaline called me telling me I ned to pay which I refused as I had not done any damage to the phone, the phone was not working properly and Magdaline the cashier told me the rep from HI had not been in th store and she dies not know how to use the mobile, and while i was in store returning the phone Gee helped me and Zanele was very rude and disruptive. I am not happy and I don't even want the phone anymore.