If you a have valid email opt in list then you can use easysendy pro or binaryclues bulk emailing software which helps you send min. 100k emails a day.
Just make sure the email I'd you have are correct otherwise you domain might get blacklisted. I will share a competitive chart below which will help you take a faster decision.
If the information was helpful, please let me know your response. I will try to assist you to my level best as I have used both of them and both are very good tools for sending millions of emails