Bad service

I had bought things from jet Westgate and when i got home i released that i was charged one thing twice so today i went to jet Clearwater for my refund for the thing that i was charged for incorrectly they told me i must bring that item to them before they do the the refund i had told them that the dress already given to my cousin in kzn they said not until i have it i wont be getting the refund....it was not my fault that i was charged the dress twice