Getting possible affiliate partners business e-mails.

Hello,

I am sorry and I am not sure if I posted in the right section. Please, mods, direct me if not. Thanks!

I have been working on a project and got a few affiliate network partnerships. Now I do need to approach partners, convince them to add the affiliate links etc. The part is clear. Where I am struggling at, is contacting with the possible partners. Support or contact forms does not give me the expected results. I have been using a few business data providers and those have to game me some success. However, I have only used it for a cheap price or free trials. Now I am looking to invest in one, but I am not sure where I should throw my money at.
Does anyone have some experience of working with these providers?

• Oxyleads.com
• Hunter.io
• Growbots.com
• Clearbit.com
• Lusha.co

Interested in the cost to quality ratio. Other implementations do not really interest me.
Thank you for every bit of info!