get SIM balance problem...

I don't understand something...

I make ussd request in mu phone:*100#

I get: Balance : 129,91,Limit 0.01

The same in arduino:

resp = modemAccess.writeModemCommand("AT+CUSD=1,\"*100#\"", 20000);
Serial.print("Responce(OK/ERROR):[");
Serial.print(resp);
Serial.print("]");
Serial.println();

I get:

AT+CUSD=1,"*100#"%13%%10%Responce(OK/ERROR):[]

I.e. I get empty string

but If I request time:

resp = modemAccess.writeModemCommand("AT+CCLK?", 20000);

I'll get time: AT+CCLK?%13%%10%Responce(time):[ +CCLK: "00/01/01,01:51:10+00"

]K I.e. "+CCLK: "00/01/01,01:51:10+00""