CMD:backup(playerid, params[])
{
    new
        string[128];
    if(groupVariables[playerVariables[playerid][pGroup]][gGroupType] == 1)
    {
        if(CallingBackUp[playerid] == 1)
        {
            SendClientMessage(playerid, COLOR_GREY, "You are already calling backup. Try /cancelbackup.");
            return 1;
        }
        if(playerVariables[playerid][pCopDuty] == 0) {
            return SendClientMessage(playerid, COLOR_GREY, "You are not on duty!");
        }
        for(new i = 0; i < MAX_PLAYERS; i++)
        {
            if(groupVariables[playerVariables[i][pGroup]][gGroupType] == 1 && playerVariables[i][pCopDuty] == 1) {
                if(CallingBackUp[i] > 0) {
                    KillTimer(CPTimer[playerid]);
                }
                CallingBackUp[i] = 0;
                format(string, sizeof(string), "SAPD HQ: %s %s is requesting backup at his location. Respond code 3.", GetRankName(playerid), GetName(playerid));
                SendClientMessage(i, COLOR_RADIOCHAT, string);
                CPTimer[playerid] = SetTimerEx("UpdateCP", 1000, true, "i", playerid);
                CallingBackUp[playerid] = 1;
            }
        }
    }
    return 1;
}

CMD:cancelbackup(playerid, params[]) //this works!
{
    if(groupVariables[playerVariables[playerid][pGroup]][gGroupType] == 1)
    {
        if(CallingBackUp[playerid] == 1)
        {
            CallingBackUp[playerid] = 0;
            KillTimer(CPTimer[playerid]);
        }
        else SendClientMessage(playerid, COLOR_GREY, "You are not calling for back up.");
    }
    return 1;
}

public UpdateCP(playerid)
{
    new Float:pos[3];
    GetPlayerPos(playerid, pos[0], pos[1], pos[2]);
    for(new i=0; i < MAX_PLAYERS; i++) {
        if(groupVariables[playerVariables[i][pGroup]][gGroupType] == 1 && playerVariables[i][pCopDuty] == 1) {
            SetPlayerCheckpoint(i, pos[0], pos[1], pos[2], 3.0);
        }
    }
}