Expired alcohol

Sam's liquor (Katlehong) they sold us expired castle lites on the 11/07/2015, after me and my friend realized on the first bottles that it tastes funny we checked the expiry date and found out that it has expired , we immidately returned them with the 2 bottles we have opened for ex-change but they refuse to take the opened ones saying it is not their fault and that they will only return the 22 instant of the whole case...the 'manager\ with attitude refused saying it is not Sam's Liquor fault (I then assume it is SAB fault)... "