Pathetic customer servece

i have bought a defy stove in protea glen ok furnitures in march they delivered a damaged Oven and the branch manager came to my house to check it out and she told me it was a factory fault ,i have been phoning them daily to exchange the oven with no luck ,i even spoke to Ishmael Moswei from defy who promised me that he will sort it out ,but each time i call defy he is always busy ,i was told that they just waiting for authorisation number for an exchange however ,i am not getting joy from defy .