Scoreboard Timer

Hi there! I am having issues with a timer! The timer works perfectly, but when it runs out, it glitches and won't start it's next task.

Code:java

    public class BuildTimer implements Runnable{
 
        public int min;
        public int sec;
        public int secTime;
        public int taskID;
        public ArrayList<Player> players;
        public Game g;
 
        public BuildTimer(int sec, ArrayList<Player> players, Game g, int taskID){
            this.secTime = 59;
            this.sec = sec;
            this.players = players;
            this.g = g;
            this.taskID = taskID;
        }
 
        @Override
        public void run() {
            if(sec == 900){
                min = (sec / 60) - 1;
            }
 
            if(sec != 0 && secTime != 0){
                sec--;
                secTime--;
            }else if(sec != 0 && sec % 60 == 15 || sec % 60 == 14 ||
                    sec % 60 == 13 || sec % 60 == 12 || sec % 60 == 11 ||
                    sec % 60 == 10 || sec % 60 == 9 || sec % 60 == 8 ||
                    sec % 60 == 7 || sec % 60 == 6 || sec % 60 == 5 ||
                    sec % 60 == 4 || sec % 60 == 3 || sec % 60 == 2 ||
                    sec % 60 == 1 ||  sec % 60 == 0 && secTime == 0){
                sec--;
                min = (sec / 60) - 1;
                secTime = 59;
                MessageManager.getInstance().msgPlayers(players, MessageTypes.INFO, min + " minutes left until the walls fall!");
                return;
            }else if(sec == 0){
                MessageManager.getInstance().msgPlayers(players, MessageTypes.INFO, "The walls have fallen!");
                g.runStage(GameStage.Battle);
                Bukkit.getScheduler().cancelTask(taskID);
            }
 
            this.scoreboardUpdate();
        }
 
        private void scoreboardUpdate() {
            if(secTime < 10 && secTime >= 0){
                sbBlue.obj.setDisplayName(ChatColor.DARK_BLUE + "Team Count: " + ChatColor.GOLD + min + ":0" + secTime);
                sbRed.obj.setDisplayName(ChatColor.RED + "Team Count: " + ChatColor.GOLD + min + ":0" + secTime);
                sbGreen.obj.setDisplayName(ChatColor.GREEN + "Team Count: " + ChatColor.GOLD + min + ":0" + secTime);
                sbYellow.obj.setDisplayName(ChatColor.YELLOW + "Team Count: " + ChatColor.GOLD + min + ":0" + secTime);
            }else{
                sbBlue.obj.setDisplayName(ChatColor.DARK_BLUE + "Team Count: " + ChatColor.GOLD + min + ":" + secTime);
                sbRed.obj.setDisplayName(ChatColor.RED + "Team Count: " + ChatColor.GOLD + min + ":" + secTime);
                sbGreen.obj.setDisplayName(ChatColor.GREEN + "Team Count: " + ChatColor.GOLD + min + ":" + secTime);
                sbYellow.obj.setDisplayName(ChatColor.YELLOW + "Team Count: " + ChatColor.GOLD + min + ":" + secTime);
            }
            sbBlue.updateScores();
            sbRed.updateScores();
            sbGreen.updateScores();
            sbYellow.updateScores();
        }
    }

If any more code is needed, I can add it!

Thanks!
~Weasel