ElecFreak 3G Shield SIM5215E no response

Hi, I recently purchased a 3G shield from Elecfreak on project to send SMS alerts with the use of Arduino UNO. Had tried the source code below but to no avail (nothing shows up when i run the serial monitor, or when i key in AT). :frowning: Hope to seek some help. Gotten a trial code online as below:

#include <SoftwareSerial.h>
#include <String.h>

SoftwareSerial mySerial(7,8);

void setup()
{
mySerial.begin(115200); // the GPRS baud rate
Serial.begin(115200); // the GPRS baud rate
delay(500);
}

void loop()
{
//after start up the program, you can using terminal to connect the serial of gprs shield,
//if you input 't' in the terminal, the program will execute SendTextMessage(), it will show how to send a sms message,
//if input 'd' in the terminal, it will execute DialVoiceCall(), etc.

if (Serial.available())
switch(Serial.read())
{
case 't':
SendTextMessage();
break;
case 'd':
DialVoiceCall();
break;

}
if (mySerial.available())
Serial.write(mySerial.read());
}

///SendTextMessage()
///this function is to send a sms message
void SendTextMessage()
{
mySerial.print("AT+CMGF=1\r"); //Because we want to send the SMS in text mode
delay(100);
mySerial.println("AT + CMGS = "+65xxxx"");//send sms message, be careful need to add a country code before the cellphone number
delay(100);
mySerial.println("How are you ?");//the content of the message
delay(100);
mySerial.println((char)26);//the ASCII code of the ctrl+z is 26
delay(100);
mySerial.println();
}

///DialVoiceCall
///this function is to dial a voice call
void DialVoiceCall()
{
mySerial.println("ATD+65xxxxxx;");//dial the number
delay(100);
mySerial.println();
}

void ShowSerialData()
{
while(mySerial.available()!=0)
Serial.write(mySerial.read());
}