Poor Customer Service

I bought a dishwasher from your Bloemgate branch and immediately tested the unit when I arrived at home. Had to take it back two hours later as it was leaking water. Got my refund back, good service. Decided to go to your Fichardtpark branch and bought a DEFY dishwasher at R1999. When i got home I tested the unit WITHOUT dishes just to confirm that it does not have water leaks, which it did not. Left for work out of town and returned a week later (last week) and started using the dishwasher. It ran the completed cycle but dishes was still dirty. I bought other even more expensive rinse aid and cleaning products, still same results. Tried to phone the Fichartdpark branch last week and Thursday with no sucess, tried to do so again on Saturday and Monday morning (the 18th of April 2022). Decided to drive all the way to store and informed them that although i dont have the slip anymore, i paid by card and there is this an audit trial of the transaction which confirm that i am the owner and bought the unit on the 30th of March 2022 at the Fichardtpark store Bloemfontein. The lady informed me that they cant help me as they need to slip as it confirms that I have signed for the warranty. This is absurd! Cash crusaders has this 6 month warranty STANDARD for all their secondhand products and I have proof that I have bought the unit two weeks ago from them, now they want to throw their hands in the air and do not want to repair my item based on a piece of paper that is missing. I was helped in the past by other major store like Game and Checkers with a bank statement when I did not have the slip anymore, so what make this so difficult for this store to understand that they are indeed able to help me? If i paid by cash then i would not had a foot to stand on, but in this case I paid by card and do have the evidence.