When I use to have the problem of too many men I didn't want, hitting on me :-) I'd get a little rude and high maintenance. If I'm helpful to someone and they start to try and cross boundaries or take advantage of me, I can point out they used my help in the first place and that I don't need the same help from them, a subtle put-down. I can get quite haughty if need be, LOL. They don't stay around.