Everyone else here has a lot of good suggestions, but the biggest thing I would recommend is NOT actively blocking them. As you already know, if you detect them

Everyone else here has a lot of good suggestions, but the biggest thing I would recommend is NOT actively blocking them. As you already know, if you detect them and make things harder...they adjust. Start with successfully detecting them and go from there. Log them. Track origins. Compile patterns. Then, when you decide exactly what you want your move to be use all that data to be as effective as possible.