Communism is both the name of the ideology and of a form of society (well defined in theory), and you need to make a distinction between the two. These countries you mentioned above were (some still are) run by communists, but were never even near communism. Nor they ever claimed that they were, most of the Eastern block countries had socialism in the name in order to make the distinction clear. Socialism is considered a transition into the real communism - which is, from all that we know now, just unachievable utopia at any larger scale than a few hundreds people.