POOR AFTER SERVICE AND WARRANTY

I bought a fridge/freezer combination on 29/12/2016. The unit suddenly stopped working. I know it has a 5 year warranty. I've misplaced the proof of purchase, but has the credit card statement. I contacted the store (Centurion Lifestyle Centre) but was informed that, unless I can provide the proof of payment, they cannot assist me because they "throw away" the books they used during the transactions after two years. I know I have to provide the proof of purchase, but I explained that I moved two times since I bought the unit. I am currently back at the address that I provided when the purchase was done, because I am in the process of buying the house. How is it possible that the store cannot be abled to assist me? Are they not supposed to have record of the transaction somewhere? I contacted the store and promises were made to phone me back, but they never did so. The telephone conversations were recorded and is available on request.