What happen if I have enabled checkout by phone number?
Recently, Shopify introduced a new way for customers to checkout, using their phone number only (without any email address). When this happens, Shopify sends their own notifications by SMS.
Our application is smart enough to detect those use cases and not send SMS in those cases to avoid duplicated messages.
But even if you have enabled this option, our application can be very useful: customers who have decided to checkout with phone number will receive SMS sent from Shopify, while customers who used their email to checkout and specified a phone number in their billing address will be notified by email from Shopify and by SMS from our app SMS notifications.