Shocking Service

I purchased a Mango shirt from Edgars for which I paid cash. I have recently lost weight and didn't realize that the size I bought was to big for me. I went to purchase a pair of boots and wanted to return the shirt as part of the price off the boots. I was told that because Mango is a brand I wont be able to return it without the slip. I have been a customer of Edgars for many years and have never heard such a policy. I am now sitting with a shirt that cost me R449 that is to big for me and they will not do anything to assist in the return. I have never worn it, the Edgars tag is attached. I am beyond upset with this. If they cannot return name brands then they shouldn't be selling them. I was in the store at 9.45 am and none of the store managers or the brand manager were at work yet. How do they expect customers to accept this type of service. I certainly won't.