I have two responses for people who say rude things to me or give me advice I didn't ask for... I smile and say
"Thanks for your concern" or "Oh, I'm sorry you feel like way"
Both usually shut the person right up because they are usually the type of person who is looking for a "debate" and that doesn't give them one (I win! LOL) or they shut up because they're too busy trying to figure out why I'm not bent out of shape by what they just said (I win again!
)