[RusIvan]

If Russia withholds gas that it agreed to provide for $50, then Russia is breaking its word, its contract, and some people would say that Russia is stealing.==

The problem is that they no conract for $50. They just lying about thier own people.
Just test. Let them go to court if they have such conract. They will not. Since they have not it.

[Cheburashka]

You say they have no contract. If there is no contract, then Russia can charge any price they want. And the Ukrainians are stealing, and will have to make good on their theft.
However, IF(and note that I said IF) it turns out that there is a contract, then the Ukrainians are only taking what is theirs by right. It is then the Russians who are stealing and will have make good on THEIR theft.
Russia, when it was an empire, and as part of the Soviet Union, has not been fortunate in its rulers. Are you so sure that that the present occupants of the Kremlin are not lying to you, as so many of their predecessors have before?
I point out that Belarus is being sold gas at $47 dollars, which is even less than Ukraine says their contract calls for them to pay. Lukashenko is a rat b-st-rd and the same as Stalin. Being in bed with him does not put Russia in the best of light. Since you hate Stalin, Lukashenko should not be on your list of friends.
I am a friend of Russia, and want this resolved as fairly as possible to all concerned. But IF there is a contract then Russia is just ensuring that that the grievances of the past will continue to be the grievances of the present. Russia and all of its neighbors need to work together for make themselves economically prosperous. Using gas supplies as a club to beat other countries is likely to damage Russia's relations with its neighbors. That puts all of Eastern Europe further behind.