SIM900A V4.0 Kit Wireless Extension Module GSM GPRS Board

Hi guys, i am a new here, i have this problem and i am working with this for a week, i don't know what to do now..i hope there is someone who can help or share their experience related to my problem..
i can't receive sms or call from my sim900a.. :confused: :confused:
i followed this code and connection with my arduino uno..

by the way i'm from philippines..