Putin is upset that Ukraine is demanding Russia cut the price of natural gas that Ukraine buys from Russia:
We are ready for a constructive dialogue, but it should not be carried out though baseless demands and ultimatums, but rather on the basis of civilized market cooperation.
The man is vaguely aware that he just took Crimea from Ukraine, right? There was no dialog. Heck, there wasn't even an ultimatum. It was just a home invasion, really.
Because if this is really a matter of who owes what to who, I'm thinking Russia will be providing free natural gas to Ukraine for a long time.