I am using Magento 2x and trying to integrate a Payment Gateway called Telr.
The issue I am facing with it is, an Order Confirmation Email is being sent the moment the customer is being redirected to Payment Gateway irrespective of the Order being Failed, Cancelled, Successful etc.
I reported the same to the Payment Gateway Company (Telr). But they said this is a flaw from Magento itself.
Then I showed them that they were wrong by using PayPal Express Checkout & Braintree Payment. Both the payment gateway worked fine, as expected, i.e, Order Confirmation Email was only being sent once the Order was SUCCESSFUL, and not immediately after being redirected to Paypayl, as it's happening with Telr. I demoed the same to them with the help of a Test Transaction via screencast.
They are still in DENIAL and saying that they cannot use Paypal's workflow as it will cause a MAJOR SECURITY LOOPHOLE. Please check attached image for screenshot of their response Email.
It would be GREAT HELP, if anybody could confirm whether what Telr is saying is TRUE OR NOT. AFAIK this isn't true.