@mgzimmer - can you provide a little more information?
were you in school in 2020? how much of the year?
how old were you on Dec 31, 2020?
were you living with your parents in 2020?
how much did you earn in 2020? (over or under $4200 is all that is important),
the answer to those questions will help understand whether they COULD claim you, which is the question you were asked on YOUR tax return (whether your parents actually claimed you or not is immaterial to solving your issue). See @Bsch4477's post - he is spot on.
