I don't know the laws of your country of residence first and foremost. But one thing I'd strongly advise you to do, is immediately, write down everything about this incident as you can. The pre-interview, the interview and the post interview that you mentioned. If you do consider either contacting a lawyer or them, about the incident, having everything in writing helps. I point this out, because, much like everyone else here, I’ve been on the receiving end of discrimination due to stuttering and another disability. The quality of the outcome of these incidences hinged strongly around how many details I had acquired. While I remembered a lot, the best results I had in rectifying and clarifying these incidences was having solid position that wouldn’t waver when emotions flared.