complaint about bas service and incompetence.

On Wednesday, the 20th of February, I asked my cousin to return a 2 plate spiral stove at Shoprite. The manager names Mrs. Williams told him the stove is loose therefore she can not exchange it. So on Saturday I went there and she said to me the stove is not in good condition to be exchanged, I asked what is a good condition? Then she said she called head office and she took pictures of the stove and the receipt and sends it to head office they advise her they can't change the stoves. I asked her what was the reason for them to say they can't change it? She said they did not say, she will call them today because they do not work on the weekend and she will call me back after. I told her this is the stove I exchange in Dec for the same problem she said yes she saw. The time now is 15:31 and she has not called me for feedback. My question is why would she change the statement she made to my cousin and stated otherwise when I went there myself? I wrote on the Shoprite contact us page this morning, and not even an email or call regarding this matter,