Putin has threatened so called unfriendly states to pay in rubles or have its gas supply shut off. It has said it doesn't buy things for free and so isn't going to charitable with its energy.
Europe has kicked against this with Germany saying its being blackmailed by this move. What other choice does Europe has with Russia alone selling about 40% of energy to the world.
At first Europe thought that if they imposed sanctions on Russia, it would weaken Russia, but without them realizing it, the sanctions had backfired on Europe itself because their dependence on gas from Russia was quite large so far,I think it's a pretty awesome trick that putin used to against europe by using the ruble as a transaction tool in the purchase of gas, if Europe does not want to do as Russia says of course the European economy will experience a bad impact, especially the industry due to lack of gas supply.