It happens more often than people would like to admit, but there is high number of misspelled email address and the number one reason some customers do not receive their license. In this case, the page https://www.avast.com/resend-license-paid.php will not provide much assistance.
The other reason, is that certain mail clients simply move the Avast email confirmation into the spam folder.
Ideally, the easiest way to locate an order is to note the order number. One can then login via www.avast.com/find-order and retrieve their licenses, invoice, enable/disable automatic-renewal, etc - among others noticing an incorrect email address.
