Make fun of yourself with them. if someone calls you an Idiot, Tell them Yeah, What an idiot am I and laugh it off. Simmilarly when someone insults you laugh with them or joke a bit about it. What I am trying to say is 'Don't let it effect you or your mood '. Slowly they will realise that there is no point of disrespecting you then it will stop one day. it may take time. Also don't act aggressively for such things. Even when I am disrespected I joke about myself. so we all laugh. They realised there is no point of disrespecting someone who doesn't give a damn about it. so now I am very good friends with them.

but even if it doesn't work, or they are disrespecting and you cannot really joke about it or can't laugh it off, then moving away 'silently' might be the best way out. That way you will be at peace and they may miss you later.