LOOSING A CLIENT OVER R60...!!!!!

Bought some care cleaning products at the shop a few days ago. Used the car shampoo and did not even clean the vehicle...I used the tyre shine and after 20min the tires went back to the dull colour it was before application. I did not even try the dashboard cleaner as two out of the three products where a disappointing. I went back to the shop 5 days later and spoke to whom I presume was the manageress and she said she would call the owner to ask if I can Swop the products for something else. She came back to me and informed me that the owner told her that I cant return the product as it was opened...I wonder how a person would find out that a product is substandard without using it. If a person buys food and you open it and the food is off would the same apply..you cant return it because you opend it. The dashboard cleaner was taken back/ I exchanged it for something else in the shop and I left the other products on the counter for the owner to clean his car with. I buy stuff regularly at the UK Emporium...Or use to...I spend sometimes R1500/ month and they did not want to return products to the value of R60...we a group of friends buying there regularly and we normally go and shop for each other.....BUT NO MORE!!!!!