How to not Buy a Mobile Phone in Moscow

I can't buy a mobile phone in Moscow. This is not to say that I can't figure out where to go, or what brand of phone I want to buy, or how to enact a basic customer-retailer interaction. This is to say that I am not allowed to buy a mobile phone in Moscow. Such is the difference between the epistemic and the deontic use if the word can't. I'm not sure what the problem is, exactly, although I think it may have something to do with, either, my interim visa, or my non-Russian passport, but at any rate, I will not be eligible for cell-phone ownership for at least another week, and probably longer; and yet, nobody seems to be able to tell me precisely what it is that makes cellular technology comparable to a firearm.