Abrasive Owner/manager at Zibaldone

My fiance and I went to eat at Zibaldone on the 11 June 2015. I ordered their Linguine ai Gamberi (Prawns, garlic, black pepper, Napoletana and cream) and when it arrived it looked lovely. But unfortunately it was short lived and as I cut into a prawn I found that it was not cleaned properly and part of the intestinal tract remained filled with black stuff. I called our waitress over and told her what the problem was and that I would like to have something else. When my new meal arrived it was brought to the table by the Owner/Manager. He proceeded to tell me that they do in fact clean all their prawns and that what I saw was actually just a black line that forms underneath the prawns shell tail. Being a keen seafood/prawn eater I knew that he was mistaken but he continued to argue with me in a forceful manner. The Owner/Manager made me feel so uncomfortable and unwelcome in his restaurant with his blatant, untactful, abrasive and confrontational approach that I was totally turned off of my new meal and the restaurant as a whole. After his departure from our table my fiance asked for the bill and we left as our whole evening out had been ruined due to this unnecessary dispute.