It's never easy. But sometimes you have to say, 'Well, it came across like that to me' and *not* let yourself be bullied into apologising to them for minding their behaviour.
As for 'So what are you going to do about it?'... I usually walk away, fast, and go to the nearest safe person I know. I lied like a trooper to that man who pushed me into his car, about the boyfriend I was meeting, and I opened the door while he was still driving and started to get out. In the phone box, I started telling the marquis (to whom I was talking) the exact address and what the young men looked like.
We scream. We yell. We make a huge fuss and attract attention. We kick and bite, if we have to. This is what I tell to my friends' daughters, now all in their teens. I want them never to feel that they are not allowed to make that fuss (which is what I felt, which is why I did nothing about the man who stalked me for a year, or about the man who insisted on spending the night in my room, or all the others, down the years).