MailboxValidator service allows you to check email address validity to reduce the number of undelivered mails. Inevitably, this will improve your email delivery success rate and reduce your bad email reputation which may result in your email address being blacklisted.
The credits will be summed up with a new expiry date based on the latest purchase. For example, suppose you have 433 credits which will be expired on 24-Sep-2013, and you buy another 500 queries plan on 22-Sep-2013. You new credits will now be 933 with the new expiry date on 21-Oct-2013.
Unfortunately, we do not control the responses from the email servers. In the case of Microsoft hosted emails like Hotmail, Live & Outlook or Yahoo hosted emails, the servers may choose not to respond to our validation requests.
Role-based emails are emails like firstname.lastname@example.org, email@example.com or firstname.lastname@example.org which may turn out to be a mailing list with multiple recipients. These email addresses are commonly rejected by email sending providers due to the fact that not everyone on the recipient list may have opted to receive your emails.