Thanks for f-ing up my birthday dinner!

we had dinner at Calisto's last night and I ordered the highly recommended queen prawns.

Dinner was served close to 40 minutes after ordering. My prawns were overcooked and extremely rubbery. I dared to complain when the waiter eventually pitched again (he never pitched during main course) and he called a manager. The manager then told me I should've notified them before eating the rest of the food, basically implying I was just hoping to get a free meal - that's after I left half of the prawns on the plate and sent it back with the waiter! I told him of the waiter's absence during main course, and he did not do or say anything! I will not be treated like sh*t as a paying customer, and your service was way below standard last night!