PICK N PAY AFTER SALES SERVICE

I purchased an Electric glass kettle from Pick n pay last December . It came with a one year guarantee. At the end of August the kettle caused a power failure in my house by tripping everything. I took it back to PNP and they said that they will send it for repairs. A few days later the manager called me and said the supplier requires the sales slip . I said i do not have it but they can check on the shopping history on my PNP Smart shopper card which has all the purchases made by me. They insisted that i must have the original slip or they cannot repair it. They refused to help me and the manager was quite rude. I went on to the PNP website where they have a forum where we could complain or compliment them on their "customer service" I wrote to them twice already in the past two weeks about this, but to date have not had any response.