We had the same situation. An automatic system informed that some info was missing or incomplete, that the NVC sent RFE.
But after we talked with operators twice we found out that everything was OK that they had not sent anything to us. That it was a mistake in the system!!!!
Finally, our case was complete on JUNE 15!!!!! Can't believe it
Please, do not worry.
Talk to an operator and find out do they really miss something