First of all we suggest that you access your reports and check the reason of complaints or cancellations. Did your contacts sign up to receive your newsletter? The higher number of cancellations is usually linked  to the contact list that you send emails to. Your list may not be updated and many of your contacts may not wish to receive your campaigns. We also recommend that you do not send too many campaigns in a short period of time and do not make your campaigns inconvenient to your contacts.