Will not exchange damaged shoes

I bought 2 pairs of shoes from Shoe City, The Glen shopping centre @ R200.00 ea, about 3 months ago. I worn the on pair about 3 times and the soul cracked, went to Shoe city at The Glen shopping centre were I have purchased the shoes and spoke to one of the sales ladies which the called the manager, I told him unfortunately I do not have the slips. He then told met that their is now way they can exchange the shoes of no slip would be produced. I explained to him that my daughter and I purchase shoe the same day and between myself and her we have misplaced the slip, I then mentioned to him that surely he could check is system and would find it that way, only to be told it would be very difficult as they sell thousands of shoes and he will not exchange un less I provide a slip. Please I did not purchase shoes @ R200 per pair only to wear for 3 months, I would appreciate if I could exchange my shoes @ The glen shopping centre were I have purchase it.