Russia is happy to do without the income in order to terrorize its coistomers. It figures such action lead to more income from obedient cutomers in the future
or did she sell elsewhere;
A bit irrelevant since Russia has huge trade surplus whether that gas/oil was sold or not sold
and did the Eastern Europeans find a way around the problem after a while or have to tough it out for a whole winter?
Was not the whole winter. Was to my memory 10-25 days
Russia has the upper hand in such situations where oil and gas are not as fungible as you theorize
I very much hope that vulnerable governments would act now in August (or even better have already acted) to lay in an emergency supply to last two weeks to a month. Maybe even more if they could afford it.
In a very real way it can be regarded as national security because IMO you are right that Russia terrorized their customers to ensure their obedience.