When a user buys a ticket, an order confirmation email is sent, in addition to an email with the actual tickets. There is not currently any built-in functionality within ET+ to send out further emails. You can however export your attendee list and then use that with a third-party plugin/email platform to send out additional emails.
We do offer full refunds within 30 days of purchase, so if you’d like to test this out, feel free to do so! Please let me know if you have any other questions.