Would this be considered slander?

Someone around your local community calls you a fag and then states it is a fact. They even say I’m just trying to help you come out because we all know you are a fag, you’re gay blah blah blah.

You argue back and say, it can’t be as I have never be gay thus it can not be a fact. If anything you believe this is slander. Would it be correct to use the word slander in this situation?