Dear sir,
I think that for your problem the best solution is a free online platform called "ReachMail"
I don't work for the company, so this is just a personal advise. I use this platform for my office work and I think it's easy and useful.
You can upload your excel list and all the invalid email addresses will be filtered automatically! Then you can see how many invalid addresses you have in your list, how many people opened your email, ecc.
I hope you'll find my advise useful!
Have a nice day!
(Just to be clear, of course I don't want to be paid for the advise, I placed a bid only to be able to write this to you. But if you'll choose this solution and you'll need assistance for using reachmail, please contact me and I'll be glad to help!)