They charged me for something I sent back

Had the wild mushroom pizza and the mushrooms were soaked in Vinegar. So the entire pizza tasted like vinegar. I had the waiter taste and he said WOW you are right. I sent it back and informed the \manager."Then when the bill came it was on there. I paid it with a scant tip and asked for the manager again. A different person showed up I complained. He said Sorry"