Each set of data should start with the string "DATA" and end with so you should only use Serial.println at the end of the data
example:
if(readsuccess){
Serial.print( (String) "DATA,DATE,TIME," +StrUID); //This data im able to generate to excel
Serial.println((String) "IKAN" +joker); //here the problem
}
also each data item should be separated by a comma