Exchange refusal

I bought a trouser at Jet Birch acres in April and within two months it had teared, I went there to return it and get an exchange but Nomusa Magubane Jet Store Admin manager refused to exchamge it for me without the cash slip, she requested that I tell her the exact date of purchase and the exact till number. As a customer how will I remember the till I bought from three months ago, that's unheard of, I'm really ****ed off by Jet and if they don't sort this I will settle my edgars account and close it for good. Worst customer service ever.