lack of service delivery

my girlfriend has purchased a pair of hollister jeans to the value of R800 on Saturday 9 may 2015 as a jean for me to use on 21 may my birthday. the size was however small hence we went to gateway edgars to exchange it for a bigger size . when we got to the store we waited behind 17 people . when we got to the desk a clerk by the name of Joel has informed us that we need the receipt of the jeans. we did explain to him that my girlfriend has misplaced the receipt but the jean had the tag with the price and code on it and that we did not want a refund bit we did want to change if for a larger size. the clerk them told us in a rough voice that the brand is not stocked at the store . I did asked if I could swap if for another jeans as I need to use it for my birthday he said in a deep voice no. I then asked if he could give us a voucher as we would like to purchase at another edgers retailer because my girlfriend did not like the manor which he addressed us in and he said no. I asked to speak to a manager or supervisor and he said he was the service centre supervisor. we demand an exchange of the jean or a voucher to buy at any edgards store<br>