Sim800C not sending and receiving sms

Hello I’m new to this project I just want to know on how I can fixed my project my sim800c does not sending and receiving a sms messages.Thank You …this is my codes

#include "SIM900.h"
#include <SoftwareSerial.h>
//If not used, is better to exclude the HTTP library,
//for RAM saving.
//If your sketch reboots itself proprably you have finished,
//your memory available.
//#include "inetGSM.h"

//If you want to use the Arduino functions to manage SMS, uncomment the lines below.
#include "sms.h"

//To change pins for Software Serial, use the two lines in GSM.cpp.

//GSM Shield for Arduino
//this code is based on the example of Arduino Labs.

//Simple sketch to send and receive SMS.

int numdata;
boolean started=false;
char smsbuffer[160];
char n[20];

void setup() 
  //Serial connection.
  Serial.println("GSM Shield testing.");
  //Start configuration of shield with baudrate.
  //For http uses is raccomanded to use 4800 or slower.
  if (gsm.begin(2400)){
  else Serial.println("\nstatus=IDLE");
    //Enable this two lines if you want to send an SMS.
    if (sms.SendSMS("91********", "Arduino SMS"))
    Serial.println("\nSMS sent OK");


void loop() 
    //Read if there are messages on SIM card and print them.
    if(gsm.readSMS(smsbuffer, 160, n, 20))

@Sukehitaro, you are aware that this is not an Arduino forum?
This forum is dedicated to Particle devices only and AFAICT there is no SIM900 library in the Particle library repository, so you may be better helped in a dedicated Arduino forum.