Auto SMS sending - Google Nexus S - Bought from Negri Electronics

I've purchased a new handset from Negri Electronics few weeks ago. Samsung Nexus S was shipped to me within a day from Negri Electronics side. Now the problem is that whenever I install a new SIM Card on my handset, a screen appears and its written [sending message] Why? I think it is not Negri Electronics because the handset was sealed piece and was in an excellent condition. So, what is the problem? And yes, my balance is also going out whenever the SIM automatically sends a message? What is this message for? Is it the MMS and GPRS settings or something else? I've contacted Negri Electronics too, and their quick response was that there might be some auto configuration sending SMS from your network provider side! Is that true? Can anyone confirm?

To be on the safe side, you can always reinstall the stock operating system... see for details on how to

i think you are using zong sim

because zong always send automatic msg on insertion of new sim and that sms is for mms and gprs settings dont worry

This is because your SIM is automatically requesting MMS and GPRS settings from your carrier.

And what should I do to disable this? Contact my service provider or Negri Electronics?

The shop where you bought it has nothing to do with it. Contact your service provider.

OK now. I've contacted my service provider and here's their reply "Your SMS/MMS, GPRS and WAP settings are always refreshed whenever you switch off your phone and put it ON. There must be a problem in your SIM CARD. Kindly come at our office and replace it". So finally the problem is not yet solved but 75% done. I will update as soon as I come up with a new SIM Card.