Exchange damaged item

I'm writing to express my disappointment with my recent shopping experience at Mr. Price Mall of the South. I purchased a pair of pants that I didn't notice were damaged until I wore them - one leg is longer than the other. Unfortunately, I no longer have the receipt and am unable to return the item. What's frustrating is that the cashier didn't inspect the pants before processing the sale. I also question how such a defective item was allowed to be sold. Despite this, I love the style and would appreciate the opportunity to exchange for a new pair. Could you please consider my request?