Tim Hortons review: ladybug in sandwich

Found a ladybug in a sandwich from Tim Hortons. It fell out of the sandwich and when I went to complain the staff just took the sandwich away and said nothing.
I had to go back up to the counter to tell them I wanted a refund. Finding a bug in a sandwich is not acceptable and they said it was probably from the lettuce. Well yes it was, but there is no reason there should be a ladybug in washed lettuce. This only means that the lettuce was not washed. As for the refund, they just put a $5 bill on the counter and walked away. I didn't receive the proper apology or customer service for this type of situation. A manager wasn't even called.