scheduleSyncRepeatingTask won't cancel

Bukkit won't let me cancel the scheduleSyncRepeatingTask method please help

public void counter(PlayerJoinEvent ingame){
getLogger().info("Counter has ran!");
final Player p = ingame.getPlayer();
getLogger().info("the total is "+total);
if (total == 4){
p.sendMessage(ChatColor.LIGHT_PURPLE+"The game will start in 30 seconds");
int l = p.getLevel();
Bukkit.getScheduler().scheduleSyncRepeatingTask(this, new Runnable() {
public void run() {
i = i-1;
p.setLevel(i);
p.sendMessage("This is a loop");
if (i == 0){
this.cancel();
}

}
}, 0L, 20L);
p.setLevel(l);

}

}