Go find investment forums/meetups like Zino Society, Keiretsu Forum, or whatever you have locally. Just attend and introduce yourself to people. Keep going back and have a simple business card to exchange information. Follow up via email. Just meet them first and talk about what your doing, but I...
Do you have an idea of what kind of invalid emails you are receiving? That will help you determine which vendor is the best fit for you. For example do you consider support@, info@, or postmaster@ invalid, some vendors will weed those out for you? Or are you just concerned with making sure the...