You should be very vigilant for a third party who might pretend to be your operator, trying to obtain your identification data and documents, with the sole aim of causing you harm (i.e. abuse these data and documents, make calls with extra costs, etc.). Here are a few examples of questions that might be illegal:

You’re asked to give a code (e.g. the PIN code of your identity card) or a password;
You’re contacted by telephone and the caller asks for your personal data;
You’re contacted by telephone or SMS, and the telephone number was hidden or foreign;
You’re contacted (by telephone, SMS, voicemail, email, etc.) and you’re invited to call back or send an SMS to a foreign paying number or a number with additional costs;
You’re asked to identify yourself using a method unannounced by us (only a Belgian payment method is valid at Mobile Vikings);
You’re invited to connect to an unsecured website ((“http://” instead of “https://”) or a website that is not officially Mobile Vikings.

SIM card identification