No, the USSR's socio-economic system wasn't true Communism because Communism desires for abolishment of money yet USSR had money system. Gaddafi too wrote of wanting human society to ultimately be rid of money. I quote a section from
part 2 of Gaddafi's Green Book :
Now since humanity doesn't have molecular replicator machines to produce things for free and since perhaps humanity needs to go to a money-less society in two steps because they have to get comfortable with the idea, for the moment we need a very simple socio-economic system where all basic necessities are free and there's an evolved money while at the same time the economic classes ( rich, middle, poor ) have been abolished and all citizens can potentially have equal access to all the other goods and services in society. In
this thread I propose such a system.
As for China, it doesn't have a mixed economic system ( what do you mean by that term ? ). Although the Chinese internal money system is called Renminbi ( People's money ) China continues to have economic classes ( very rich, rich, middle, poor ), has privatization of even basic services like housing and healthcare and has the stock market system where the system allows citizens to gamble, lose money and suicide :
Man in China jumps into steel furnace and dies after reportedly losing money on stock exchange A steelworker was caught on surveillance camera jumping into a blast furnace in China, local police have reported The man had allegedly accrued large financial losses trading in stocks, his colleagues...
defence.pk
China must adopt a Communistic socio-economic such as the one I propose.
I will tag
@Wergeland because you quote him.