The quote by Putin which says it all...

My Bulgarian colleagues have always told me that whatever happens, they would certainly implement South Stream, because this corresponds to their national interests. But here, unfortunately, this did not come to pass. If Bulgaria is deprived of the opportunity to act as a sovereign nation, then they should at least demand money from the European Commission to compensate for their lost profits, because direct revenues to Bulgaria’s budget alone would have been no less than 400 million Euros a year. But ultimately, this is also the choice of our Bulgarian partners; it seems they have certain obligations. Still, that’s not our business – it’s our partners’ business.

Vladimir Putin