First well published incident was cutting off Estonia in 1993, right after it regained independence.
Note Russia always does something to shift the blame, usually starts "dispute" over payments. It's done because media need to report ”balanced" view, so just by reading general news it's not apparent tha this is really blackmail. Stockholm tribunal regularly disproves Russian version, it just takes time, which is what Russia is after: you can't survive winter without heating, and the final verdict won't arrive in time. So until LNG terminals and pipelines to Norway sprang around the Baltic Sea, coupled with Third Package, Eastern Europeans mostly had to yield to this blackmail.
> The only time when we had issue with gas
ISTM you live west of Oder. No one in Eastern Europe would say this.
> it was some ten years ago when Ukraine stopped the transit hoping to blackmail both Russia and the EU to get a better deal for themselves. Ukraine was a failed state then that couldn't pay for gas they used.
This is false, Ukraine wasn't "failed state". What failed was an attempt to rig an election.