Help! I have to retake my english controlled asessment for using profanity, is this fair?

I'm doing GSCE English, and we were given a controlled asessment to write a rant about something that annoys you. I used profanity, because if something annoys me I always will. I have been told that I need to retake this and that the head of the english department wants to have a discussion with me. This has ruined my good mood, can they do this?