Why would you do that sort of roundabout route when you could just trade rubles for other currencies directly?
Plus selling the phone back to get rubles doesn't seem like a smart move unless you think you've timed the bottom and the ruble isn't going to slip further against the dollar. Doesn't seem like people really think that.
At the moment, people would rather hold iPhones than rubles. I don't think that's in an attempt to turn a profit, it's just because an iPhone (or a major appliance, or a computer) is perceived to be a better store of value than rubles. Which given how electronics depreciate, is a really bad sign.
That time they've raised the prices to compensate without closing the shop altogether.