Response USSD with SIM900 trouncated

Hi,
I’m tring to send a USSD string with SIM900, but response is trouncated.
My code:

mySerial.println(“AT+CMGF=0”);
delay(100);
mySerial.println(“AT+CUSD=1,”*123#"");
delay(5000);
char c;
int count = 5;
while(count-- != 0) {
delay(100);
while (mySerial.available() > 0){
c = (char)mySerial.read();
Serial.print(c);
}
}

How to resolve the problem?
Thanks a lot