“Since Russia owns the commodity it seems reasonable that they would make such a decision.”
Did Russia stipulate in the contract that payments can only be made in rubles? I doubt it, since when the contracts were negotiated and signed the ruble was not a very secure or stable instrument or medium of exchange.
From what I know the situation I feel Russia is completely justified. You can’t just steal reserves, sorry. Now that they’ve taken that step it’s hard to blame Russian for not wanting to hold more of those “reserves” when it’s easily stolen.