I would suggest that the best place to ask this sort of question would be the web site of the authors of the webservice.
Still, if it were me I would try by replacing the
references with the actual values.
Lable1.Text=sendSms.sendSmsSpiritsSoft("yourUsername", "yourPassword", "7845111222", "Hello World");
Obviously use the real usename/password and a real mobile number.
If that works then there is something wrong with the values in your
es, maybe spaces in the wrong place etc.
However, if that doesn't work then you have done something wrong somewhere else. Which will mean a visit to the authors web site. There must be tutorials there.