How to verify big email lists? Searching for cheap solution…

Hi, don`t know where is the right place to post this thread, so I am sorry if needed mods, please move it to the right place.

So, i have big amount of email lists, targeted and want to clean invalid emails. I started campaigns with Mailgun but i am getting around 8% bounce rate, because of invalid/not existing mailboxes. In result of this my sending domain is getting limitation.

For this i tried some cracked apps but all are broken,…

How to verify big email lists? Searching for cheap solution…