My provider doesn’t allow sending bulk mails

Your provider doesn’t allow you to send bulk mail or even block outgoing mail completely. You can always use a dedicated email provider:

• SendGrid
• Mandrill
• Amazon SES
• SparkPost

If Mailster doesn’t come with a dedicate add-on for your email provider you can always fall back to SMTP.

Please check out the free plugins for available delivery methods on the WordPress repo.