Pep Stores review: Refund without original slip

I purchased some men underwear on Sunday 1 March, at Pep Elarduspark and it is unfortunately the wrong size. The original slip was discarded and I no longer have this. I do have my proof of transaction from my bank.

The underwear was not even opened, this is still in the original packaging. Could I possibly get a refund without the original slip?

I find this discomforting that I am not able to return the goods (in original packaging) for a refund.

View 0 more photos