Not able to recieve message sent from mobile to GSM SIM900 but other functionalities working

Question

Not able to recieve message sent from mobile to GSM SIM900 but other functionalities working.

I think there is something related to AT command. Please help me that and thank you.

/*THIS TUTORIAL USED GSM SIM900A MINI V3.9.2
 
  Connect 5VT to D9 and 5VR to D10
  Feed GSM SIM900A with Arduino's 5V

  Code by IDAYU SABRI - MYBOTIC
*/

#include <SoftwareSerial.h>

SoftwareSerial mySerial(3, 2);

// phone number
char PHONE_NUMBER[13] =  "+918380843911";

char msg;
char call;

void setup()
{
  mySerial.begin(9600);   // Setting the baud rate of GSM Module  
  Serial.begin(9600);    // Setting the baud rate of Serial Monitor (Arduino) 
  Serial.println("GSM SIM900A BEGIN"); 
  Serial.println("Enter character for control option:"); 
  Serial.println("h : to disconnect a call"); 
  Serial.println("i : to receive a call");
  Serial.println("s : to send message");
  Serial.println("c : to make a call");  
  Serial.println("e : to redial");
  Serial.println();
  delay(100);
}

void loop()
{  
  if (Serial.available()>0)
   switch(Serial.read())
  {
    case 's':
      SendMessage();
      break;
    case 'c':
      MakeCall();
      break;
    case 'h':
      HangupCall();
      break;
    case 'e':
      RedialCall();
      break;
    case 'i':
      ReceiveCall();
      break;
    case 'rm' :
      ReceiveMessage();
      break;
  }
 if (mySerial.available()>0)
 Serial.write(mySerial.read());
}

void SendMessage()
{
  mySerial.println("AT+CMGF=1");    //Sets the GSM Module in Text Mode
  delay(1000);  // Delay of 1000 milli seconds or 1 second
  mySerial.println("AT+CMGS=\""+ String(PHONE_NUMBER) +"\"\r"); // Replace x with mobile number
  delay(1000);
  mySerial.println("sim900a sms");// The SMS text you want to send
  delay(100);
   mySerial.println((char)26);// ASCII code of CTRL+Z
  delay(1000);
}

void ReceiveMessage()
{
  mySerial.println("AT+CNMI=2,2,0,0,0"); // AT Command to recieve a live SMS
  delay(1000);
  if (mySerial.available()>0)
  {
    msg=mySerial.read();
    Serial.print(msg);
  }
}

void MakeCall()
{
  mySerial.println("ATD+" + String(PHONE_NUMBER) + ";"); // ATDxxxxxxxxxx; -- watch out here for semicolon at the end!!
  Serial.println("Calling  "); // print response over serial port
  delay(1000);
}


void HangupCall()
{
  mySerial.println("ATH");
  Serial.println("Hangup Call");
  delay(1000);
}

void ReceiveCall()
{
  mySerial.println("ATA");
  delay(1000);
  {
    call=mySerial.read();
    Serial.print(call);
  }
}

void RedialCall()
{
  mySerial.println("ATDL");
  Serial.println("Redialing");
  delay(1000);
}

All the connections and power supply of GSM as well as Arduino is correct.

To recive message sent from mobile to GSM and read it.