If your customer does not receive email notifications from the merchant, there are a few possibilities:
The email settings (Settings - General - Email) are not configured properly. To amend, follow the step-by-step guide here.
Sender’s email has been changed. We are not authorised to send emails on behalf of other domains. Hence, it is highly advisable to use firstname.lastname@example.org as the “Sender’s Email”.
For collection reminders, “Send Reminder to Customers” checkbox was not selected when generating the collection.
There could be an issue with the email server, kindly contact our Person-In-Charge at email@example.com for assistance.
If your customer still does not receive email notifications after all the above have been checked, advise your customer to check their junk/spam mailbox.