Review TELEFUNKEN TABLET

We bought a tablet at the Carletonville branch that is advertised for R989.00 and left the store...we tried to start the tablet but it did not work. Went back to the store to tell them it was broken in which the salesperson replied yes he knew it was not working as somebody else returned it and showed me the marks on the side of the phone. He wanted me to go to the other branch at Gateway mall in which I replied it is not my duty so he went there and came back with another phone. Now I gave the present to my son and again the new one is not working either..... How do I get my money back because obviously this is not a good buy!!!