Slip and transaction number

I bought items on the 23rd December 2017 at Mr. Price Tygervalley. Unfortunately I loose slips so I take pictures of my slips and keep them as proof. I then went back to Mr. Price today 13th January 2018 with the picture of my slip which contains all the details I require for a refund even the transaction number and everything and they refused to refund me. I am not very happy at all and I want my refund. The staff in the store is very unprofessional to deal with.