I was forced to pay for a meal that I couldn't eat

I ordered a calamari salad & I had asked if the calamari could please be grilled instead of deep fried as I was eating healthy. My food was brought to me with deep fried calamari, the waitress told me that they were unable to grill it and I said no problem. I had taken one bite of my salad and the calamari tasted excessively fishy as if it were old. I explained to the waitress that I was not happy with my meal and that the calamari tasted old, she went to the kitchen. The waitress told me that the calamari had been delivered yesterday and it could not be old. I told her that I can't eat this and would like to change my order, she called for her manager. He came out and spoke to me after 5-8 mins. I explained to him that I can't eat the salad, he told me that the calamari was delivered yesterday and that it can't be old. He refused to let me change my order and offered to fry the calamari more because he said it didn't look brown enough. I refused because I couldn't eat the calamari at all. The manager did not budge, I did not eat the meal and was still charged for it. The calamari looked old and the manager was absolutely unreasonable. It's sad that we pay so much for ****