IOT based vehicle tracking system using arduino

In this project , I use tracking shield sim 900 from Rhydoz lab which is a development board designed for tracking .It consists of GPS/GSM/GPRS in it .The main idea is to detect location and interface it with google maps so that we get location details of a vehicle to which it is set ,the location is sent as message to the mobile number programmed .But the problem is that I'm getting latitude and longitude but I'm not getting message to the prgrammed mobile number nor AT commands is working .so i need help in this project who have a good knowledge in embedded c