block calls based on a blacklist file

 exten => _X.,1,NoOp(${CALLERID(num)}-${EXTEN})

same=>n,Set(BAN=${SHELL(cat /home/centos/spam.conf  | grep -w -F ${CALLERID(num)} | wc -l)})

same=>n,ExecIf($[${BAN}>0]?hangup())

same=>n,Noop(***${BAN}***)

*content of  /home/centos/spam.conf **

188222

22222

33333