Ok but Lenin's Soviet Union under the NEP was not a communist society, it was at best a transitional state. So by ignoring what Marx said would be required in the transitional state, you could say that Lenin did lots wrong, according to Marx, which is how this conversation started.
Transitional societies are necessary for the finished product, by definition. You can't go from 1 to 3 without passing through 2. Marx gave us a picture of both, though it was never in any way complete. Rather than an N+1, communism is N-1. It's all of this minus its socioeconomic laws, not with more of them.
Marx told us what isn't permanent and, thus, what to abolish, not what to create.
Even without NEP, in a more advanced post-capitalist stage, it would've still been transitional. Please, do learn what basic cause and effect are. It's just basic logic.
What did he ignore?