Need Help. sms.SendSMS() interferes with my constant strings.

Using Arduino Programming Questions
1

Hello. I am having problems with my strings when I start implementing the sms.sendSMS. It seems that whenever I start using the sms.sendSMS, whatever i try to put inside the strings, nothing is stored.

without the sms.sendSMS, my serial monitor would print out:

09052391306
on 15
COMMAND GRABBED:
ON
NUMBER OF MINUTE(S):
15
IN MILLISECONDS:
900000

but with the sms.sendSMS, my serial monitor would print out:

09052391306
on 15
COMMAND GRABBED:

NUMBER OF MINUTE(S):
0
IN MILLISECONDS:
0

i need the the gsm module to tell me when the time is up, so i badly need the sms.sendSMS to work together with my strings.
here is my code:

#include "SIM900.h"
#include <SoftwareSerial.h>
#include<Servo.h>

#include "sms.h"
SMSGSM sms;
Servo myservo;
/****************************************************************************************************/
boolean GSMactive = false;
char smsbuffer[160];
char n[20];
char remoteNumber[20];

String intString = "";
String charString = "";

int minute = 0;

unsigned long int timeMillis = 0;
unsigned long int timeExact = 0;
unsigned long int activeRead = 0;
unsigned long int startRead = 0;

unsigned long int timeLeft = 0;
unsigned long int runTime = 0;

boolean timerActive = false;
boolean finalCount = false;

const int redLed = 4;
const int greenLed = 5;
const int blueLed = 6;
const int pwrON = 9;
/***************************************************************************************************/
void setup(){
  pinMode(redLed, OUTPUT);
  pinMode(greenLed, OUTPUT);
  pinMode(blueLed, OUTPUT);
  pinMode(pwrON, OUTPUT); 
  Serial.begin(9600);
  digitalWrite(redLed, HIGH);
  pwrOn();
  Serial.println("DEVICE LOADING...");
  if(gsm.begin(9600)){
    Serial.println("STATUS = DEVICE READY");
    GSMactive = true;
    digitalWrite(redLed, LOW);
    digitalWrite(greenLed, HIGH);
  }
  else{
    Serial.println("STATUS = DEVICE IDLE");
    digitalWrite(redLed, LOW);
    digitalWrite(blueLed, HIGH);
  }
}
/****************************************************************************************************/
void loop(){
  intString = "";
  charString = "";
  minute = 0;
  activeRead = millis();
  
  if(timerActive){
    runTime = activeRead - startRead;
    timeLeft = timeExact - runTime;
    Serial.println("TOTAL RUN TIME:");
    Serial.println((float)runTime/60000);
    Serial.println("TIME REMAINING:");
    Serial.println((float)timeLeft/60000);
    delay(500);
  }
  
  if(timeLeft < 30000 && timerActive){
    Serial.println("LESS THAN A MINUTE LEFT");
    finalCount = true;
    GSMactive = false;
  }
  
  if(finalCount && timeLeft < 1000){
    Serial.println("TIME UP!");
    timerActive = false;
    finalCount = false;
    GSMactive = true;
    switchOff();
    sms.SendSMS(remoteNumber, "TIMER OUT. DEVICE DEACTIVATED!");
  }
  
  if(GSMactive){
    if(gsm.readSMS(smsbuffer, 160, n, 20))
    {
      Serial.println(n);
      Serial.println(smsbuffer);
      
      for(int index = 0; smsbuffer[index] != '\0'; index++){
        int thisChar = smsbuffer[index];
        if(isDigit(thisChar)){
          intString += (char)thisChar;
        }
        if(isAlpha(thisChar)){
          charString += (char)thisChar;
        }
        if(isPunct(thisChar)){
          charString += (char)thisChar;
        }
      }
      for(int num = 0; n[num] != '\0'; num++){
        remoteNumber[num] = n[num];
      }
      charString.toUpperCase();
      minute = intString.toInt();
      timeMillis = minute * 60000;
      
      Serial.println("COMMAND GRABBED:");
      Serial.println(charString);
      Serial.println("NUMBER OF MINUTE(S):");
      Serial.println(minute);
      Serial.println("IN MILLISECONDS:");
      Serial.println(timeMillis);
    }
    if(charString == "ON"){
      Serial.println("TURNING DEVICE ON...");
      if(minute <= 15 && minute > 0){
        startRead = millis();
        timerActive = true;
        timeExact = timeMillis;
        switchOn();
        sms.SendSMS(remoteNumber, "DEVICE ACTIVATED!");
      }
      else Serial.println("ERROR!");
    }
    if(charString == "OFF"){
      Serial.println("TURNING DEVICE OFF...");
      if(timerActive){
        timerActive = false;
        switchOff();
        sms.SendSMS(remoteNumber, "DEVICE DEACTIVATED!");
      }
      else Serial.println("ERROR!");
    }
    if(charString != "OFF" && charString != "ON"){
      Serial.println("DO NOTHING.");
    }
  }
  Serial.println("LOOP ENDED...");
}
/****************************************************************************************************/
void switchOn(){
  myservo.attach(10);
  for(int pos = 0; pos < 180; pos++){
    myservo.write(pos);
    delay(15);
  }
  myservo.detach();
  return;
}
/****************************************************************************************************/
void switchOff(){
  myservo.attach(10);
  for(int pos = 180; pos >= 1; pos--){
    myservo.write(pos);
    delay(15);
  }
  myservo.detach();
  return;
}
/****************************************************************************************************/
void pwrOn(){
  digitalWrite(pwrON, LOW);
  delay(1000);
  digitalWrite(pwrON, HIGH);
  delay(2000);
  digitalWrite(pwrON, LOW);
  delay(3000);
  return;
}
/****************************************************************************************************/