php - Braintree webhooks, GET & POST configuration -

i trying use webhooks send emails whether subscriptions charged or not. use bt_challenge code register webhook on braintree's dashboard:

if(isset($_get["bt_challenge"])) {     echo(braintree_webhooknotification::verify($_get["bt_challenge"])); } 

however, when use subscription information $webhook notification:

if(isset($_post["bt_signature"]) && isset($_post["bt_payload"])) {     $webhooknotification = braintree_webhooknotification::parse(         $_post["bt_signature"], $_post["bt_payload"]     ); }    

i don't email sent. furthermore, when try re-register webhook braintree dashboard, won't recognize second snippet of code in file. both of these snippets meant in same file? part unclear me.

following these 2 snippets, have phpmailer code, configured , sends email when script called not via webhook. phpmailer code not contained within "if" statement of either of these first 2 code blocks.