Arduino Count Down Timer Loop

Hello, I just began learning arduino and I just want to make a simple count down timer with a single push button with a start/restart function. I successfully managed to start and restart the timer and display it to the lcd but after the timer completes, it automatically restarts and begins to count down. I do not currently know what is causing the loop, I tried changing my count value after completion but it doesn't help.

Here is my code. Thank you.

#include <LiquidCrystal.h>
#include "Countimer.h"

Countimer tDown;
Countimer tNone;

LiquidCrystal lcd(2, 3, 4, 5, 6, 7);

int switchPin = 8;
int ledPin = 13;
int count = 0;

boolean lastButton = LOW;
boolean ledon = false;
boolean currentbutton = LOW;



void setup()
{
  Serial.begin(9600);
  pinMode (switchPin, INPUT);
  pinMode (ledPin, OUTPUT);

  
    // Count-down timer with 21s
  tDown.setCounter(0, 0, 10, tDown.COUNT_DOWN, tDownComplete);
    // Call print_time2() method every 1s.
  tDown.setInterval(print_time2, 1000);

    // No counter
    // Just call print_none() method every 2s.
//  tNone.setInterval(print_none, 2000);
}
boolean debounce(boolean last)
{
  boolean current = digitalRead(switchPin);
  if (last != current)
  {
    delay (5);
    current = digitalRead(switchPin);
  }
  return current;
}
void loop()
{
  
  tDown.run();
//  tNone.run();
  
  
  currentbutton = debounce(lastButton);
  if (lastButton == LOW && currentbutton == HIGH)
  {
    ledon = !ledon;
  }
  
  lastButton = currentbutton;
  if (ledon == true)
  {
    count = 1;
  }
  else
  {
    count = 0;
  }
  switch(count)
  {
    case 0:
    tDown.stop();
//    lcd.clear();
    print_time2();
//    tNone.stop();
    
    break;

    case 1:
    tDown.start();
//    tNone.start();
    break;

    default:
    break;
  }

}


void print_time2()
{
  Serial.print("tDown: ");
  Serial.println(tDown.getCurrentTime());
  lcd.clear();
  lcd.print("Time: ");
  lcd.print(tDown.getCurrentTime());
}
//
//void print_none()
//{
//  Serial.print("tNone: millis(): ");
//  Serial.println(millis());
//}


void tDownComplete()
{
  lcd.clear();
  lcd.print("COMPLETE!!");
  Serial.println(count);
}

You may need to stop the timer when it gets to 0. You do need to post a link to the library you are using.

What you want to do doesn't really require a library.