Found slug in pizza, rudely dismissed by owner

In December 2018 my friends and I went to the Col’cacchio at the Mall of the South. We order two pizzas one of which was the Green Genie. This is the pizza with a whole lot of fresh greens, rocket and baby spinach. My friend started eating her pizza when she can accross a slug. The slug was still alive. This is extremely dangerous as slugs are known to cause paralysis. My friends and I were extremely disgusted but also understating that these things happen. When working with fresh greens , it is understandable - unacceptable but still we calmly called the waitress who in turn called the manager. We didn’t want to cause a scene or ruin anyone else’s night out. The manager was extremely apologetic, he even went so far as to call the kitchen stall responsible for washing the greens to our table to apologise and to make him understand the seriousness of the mistake. The manager and his staff handled everything with due respect and appropriateness. We accepted the apology and ordered another pizza. At the end of our meal we asked for the bill and we’re shocked to see that we had been charged for everything, including the contaminated pizza. We then explained to our waitress that our calmness in dealing with the situation does not take away from the seriousness of the situation. It is common courtesy to trim the bill in such instances. We then get rudely approached by the owner (we presumed). He didn’t greet , he made no apology. He snidely asked us what we would be happy paying for? We were so taken aback my his extreme arrogance and rudeness and we simply responded that we have been extremely patient and understanding but that it is their responsibility to decide how to compensate us for our horrible experience. He rudely dismissed us and walks away. The waiter returns with a bill that had been trimmed to half. We were extremely shocked at the owners rudeness and lack of respect in dealing with the matter. He almost made it seem as though he was doing us a huge favor. I vowed to tell everyone about our atrocious experience and never to return to any Col’cacchio ever again.