Refusal to Assist

On 03/07/2015 I went to Foschini in Randburg and bought a few items, I then went to TotalSports and made one more purchase. When I was done I still had credit left left. On 14/07/2015 I went back to Foschini Randburg to return a pair of pants however when I checked my slip I was not credited for the pants. I went to the store again and spoke to a very helpful Sibongile who called customer care to try and get an an explanation. The first consultant she spoke to gave her some some story I could not understand, she then called again and requested the second agent (Thuli) to explain the account to me. Thuli refused to speak to me and she also refused to send me a detailed statement for the account AND, according to Thuli, Foschini agents are not allowed to give out their surnames(very strange). I pay this account without fail EVERY month so I do not understand why Foschini thinks it's above explaining why I was not credited. I hope to get assistance soon.