Blocking spam when sending notifications in the catalog.

I bought a script from the catalog of organizations and companies, I uploaded more than 2 million companies. During the activation of each organization, a notification was activated.
As a result, the entire site host for spam was reduced. I went to another. Completely disconnected the entire account.
Where can I find a normal host that does not crash to send by mail? Or maybe there are some other solutions?
By the way, the newsletter also receives spam, even when it comes to it. This is not …

Blocking spam when sending notifications in the catalog.