I've purchased a Smarty data sim and was going to use it with a 3 mifi unit I have had for a few years. I put the sim in and it connects to my laptop fine but it is not password protected so anyone can use my data! I can't find out how to put a password on it and as the mifi is quite a few years old anyway (3g) i'm thinking of getting a new unit. Does anyone have any recomendations please?