If you do not want to verify a particular domain in your list, there is an option to remove it before validation.
Once your list has been uploaded, You will have the option to View more details of this list.
Click on View more details of this list and you will see a list of the domains that are in your list.
Clicking the cross next to domain will prevent it from being verified.
Your data for these emails will not be deleted or modified in any way.