Spam and scam, and if there is a optional comment section, explain the situation as you see it there. YouTube will handle it from there, though I am not sure how effective that will be.

You cannot catch them all, so long as you report it then you have done all you realistically can do. Sure, you can stalk the user and confront them (dangerous, and probably illegal so don’t do that) or harass YouTube via email (annoying and causes unnecessary strain on their employees trying to do other work), but the best thing you can do is report it and leave it up to YouTube. At that point if they choose to do nothing, you did your best and the blame for enabling that kind of behavior is entirely on YouTube.