Arduino with Wavecom Fastrack

I have a project control arduino with modem wavecom fastrack m1306b serial.
I have attached the source code. (code reference: Stackoverflow)

But, when inside loop
if(buttonStat == 0 && kunciFlag == 1){
setSirine(1);
sendSMS(“warning1”);
}
else
{
setSirine(0);

Arduino will send sms for multiple times and the sirine sound like its always looping.
But when the sendSMS(“warning1”); disabled, the sound run normaly.

Anyone can help me please?Cause it very urgent

Thanks before ^^

Tugas_Akhir.ino (8.32 KB)