Hello friends
I’m using this wiki : http://wiki.mikrotik.com/wiki/Payment_Reminders to redirect requests and active payment reminder .
But finished credit users can send data (see below scenario , user can connect l2tp connection or some like) :
User torch , user can send packet data as dns to dns server , or send http or https requests to out of network servers .
How to block or prevent users to send data to outgoing network ? 
thanks