I’m not looking for the actual list of emails. I need to speak with the owner of the company that has this list of clients. thanks
I don’t want to buy an email list, I want to get in touch wibusiness owners who have a large client (email) list

Our Website is a vacation rental directory. People frequent our site to place inquiries for homes which owners showcase on our directory. When they inquire they opt into receive information from us. Does anybody have any recommendations for a list management system that can handle hundreds of thousands of email addresses without being incredibly strict on complienace. We’ve used some before but they tend to be for smaller businesses. What company works well for corporations or large companies like ours?