door protector using arduino uno and GSM sim800 module

Please check the arduino program given below and help me to find out error. The program is for following hardware. GSM 800 module Arduino Uno board Limit switch(2)

We place two limit switch at main door & back door as main door is open the message will be send that is Main door is open & when it closed it will send message Main door is closed. This is same for Back door also.

We run this program & it run but it sends the massage repeatedly after some time. Please help me to find out error..

    const int Main = 7;
    const int Store = 8;
    const int Main_led =  13;
    const int Store_led =  14;
    bool i = false;
    bool j = false;
    bool k = false;
    bool l = false;
    int buttonState1 = 0;
    int buttonState2 = 0;
    void setup() {

      Serial.begin(9600);
      pinMode(Main_led, OUTPUT);
      pinMode(Store_led, OUTPUT);
      pinMode(Main, INPUT);
      pinMode(Store, INPUT);
    }

    void loop() {
      buttonState1 = digitalRead(Main);
      if (buttonState1 == HIGH && i == false ) {
        digitalWrite(Main_led, HIGH);
        Serial.println("OK");
        delay(1000);
        Serial.print("AT+CMGF=1\r\n");
        delay(500);
        Serial.print("AT+CMGS=\"+91-------------");
        Serial.print("\"\r\n");
        delay(5000);
        Serial.print("Main Door is closed");
        Serial.write(0x1A);
        delay(5000);
        i = true;
        j = false;
      }
      else
      { if (buttonState1 == LOW && j == false )

        { digitalWrite(Main_led, LOW);
          Serial.println("OK");
          delay(1000);
          Serial.print("AT+CMGF=1\r\n");
          delay(500);
          Serial.print("AT+CMGS=\"");
          Serial.print("+91---------------");
          Serial.print("\"\r\n");
          delay(5000);
          Serial.print("Main Door is open");
          Serial.write(0x1A);
          delay(5000);
          i = false;
          j = true;
        }
      }

      buttonState2 = digitalRead(Store);
      if (buttonState2 == HIGH && k == false) {

        digitalWrite(Store_led, HIGH);
        Serial.println("OK");
        delay(1000);
        Serial.print("AT+CMGF=1\r\n");
        delay(500);
        Serial.print("AT+CMGS=\"");
        Serial.print("+91-------------");
        Serial.print("\"\r\n");
        delay(5000);
        Serial.print("Store room is Closed");
        Serial.write(0x1A);
        delay(5000);
        k = true;
        l = false;
      }
      else
      { if (buttonState2 == LOW && l == false)
        {
          digitalWrite(Store_led, LOW);
          Serial.println("OK");
          delay(1000);
          Serial.print("AT+CMGF=1\r\n");
          delay(500);
          Serial.print("AT+CMGS=\"");
          Serial.print("+91------------------");
          Serial.print("\"\r\n");
          delay(5000);
          Serial.print("Store room is Open");
          Serial.write(0x1A);
          delay(5000);
          k = false;
          l = true;
        }
      }
    }