Question

today i would ask you if someone know how Check if the user has really payed and then if he has really payed execute some mssql+script

for be precise if he has really payed i would execute this query via php:
(UPDATE members SET Premium=’1′ WHERE membername=”‘.$membername.'””)

Answer 1

You can check this PHP example from paypal site:

https://cms.paypal.com/cms_content/US/en_US/files/developer/IPN_PHP_41.txt

if (strcmp ($res, "VERIFIED") == 0) {
// Your code
}