[bullen]

Yes, in this case "security" by obfuscation is the only way to go.

I have a tip for people that don't like to be called by sales people. Buy two simcards, the first should be as anonymous as possible (cashcard or equivalent) then later buy a real subscription one, if you are lucky the subscription one will overwrite the cashcard number in all official indexes and you can use the first in your mobile and the second (that gets all the spam) in a mobile router for internet only.

Works for me and it's a life saver!