Chicken is not vegetarian!

On a recent business trip, I took a Sunday afternoon BA flight from Johannesburg (O.R. Tambo) to Cape Town International Airport. My booking was done by a travel agent from whom I received a booking confirmation number. I used the 'Manage my booking' functionality to book a special meal as I am a vegetarian. On the website [URL Removed] the Hindu meal option is described as ' Does not contain: fish, shellfish, meat, poultry or eggs. This is a meat free, spicy meal.' Why then was I served chicken in my Hindu meal??