Despicable Behaviour

My partner and I on our way home from a long day decided to quickly pop in to Funtastico for a meal. We were welcomed by the apparent owner, and then by perhaps his wife and also apparently an owner. However, from the start she was not very welcoming, and didn't even speak when we asked to go to a particular table, just pointed at it. It may be necessary to mention that I am 'white' and my partner 'non-white'. It seemed that when she saw my partner, she immediately turned cold. Anyhow, we sat down and had a meal and while eating desert she went into the part of the kitchen that is seperated from the restaurant by a bar-tyoe counter, so one can see and hear what is going on in this part of the kitchen. She was shouting at two staff members in the kitchen for apparently making a mistake on an order, and although I couldn't hear all of what she was saying, could here her telling them that they are stupid, to shut up etc. She also openly spoke very rudely and disrespectfully to her staff on the floor, indicating to us I'm afraid a quite ****** attitude to her staff. So I went up to her and told her that, firstly, it is completely unacceptable to belittle and disrespect anyone, as she was doing to the kitchen staff. Secondly, that it is also unacceptable for her to behaving as she was where customers could see and hear her. She asked, 'You're telling me what is acceptable in my restaurant?'. I said 'Yes, as a customer I am certainly telling you what is acceptable.' She responded, 'What customer? You don't need to be my customer. Go somewhere else if you don't like how I do things here.' I couldn't believe her intransigence and attitude and told her that I was shocked at her behaviour, is this honestly her response?. She continued to just say, 'Go on, get out of here.' I then unfortunately had to pay the bill by card through her, and again she was aggressive and arrogant. Still cannot believe that an owner of a restaurant would behave like this. What else to do?