Worst customer service I have ever experienced

So today I went to a pet store which my partner and I religiously support. We have always been good customers. Today I went to buy another pee mat for my dogs pee tray. A tray set that I previously bought on recommendation from the owner who at the time said I could get more mats. Now a few months down the line I went back to buy an insert. The staff looked and told me they were out of stock. I asked the lady on duty whether she could get me one and if so I would the complete set they had, i reiterated but if only they could get me another insert, and we would then have two complete sets. (Not that we need two, I just wanted the insert for the interim). So I spent R1081 on the complete set. The lady on duty asked one of the staff if she was sure there was not one in the stockroom, unfortunately not. The lady who did the sale wrote down my details and said she would get back to me. When I left the store I was messaged the owner whom I always deal with and was told they don’t get inserts. I then went back into the shop to find the lady who helped me on the phone with the owner whom I had messaged. She was whispering on the phone. I asked for a credit and she said they would only give me a store credit, I admittedly said FFS - then why did you sell it to me if I can’t get inserts (clearly they didn’t know this and couldn’t admit they made a mistake). She said the owner will call the supplier and if they have a broken tray there I can get the insert (if? - I only made the purchase on the request that I could get another insert). The lady who helped me at this time phoned the owner again (clearly in breach of ethical customer service (I did record her) l, she manipulated the story and said I was swearing at her and the store was full of people, a blatant lie. I then called the owner who did not listen and frankly just screamed at me and told me she has an op tomorrow and I am responsible for stressing her out. She would not listen and just said I must listen to her ? A wired concept ad I am a shop owner and I listen to my customers and try call them down. My point to her was why sell me another complete set of you cannot guarantee me an insert ad requested for my existing tray. It was at this point she told me she was surprised at my behavior and told me to f-off and hung up the phone. We visit this store every two weeks and spend mostly over a 1000+ here. Clearly bully tactics work in this store for them. They didn’t have their facts straight and have lost a good loyal customer who refers many people to them. Not again, I have left the store feeling totally despondent, actually it’s quite heartbreaking that you can give people your business just to be treated like rubbish. But maybe I am to blame as I have seen other customer get treated like this in the past and I always wondered what they must have done wrong. Don’t allow yourself to be bullied by shop owners. Their website under construction and they appear to have no email address listed