For your theory to be true....your "universe" has to be and not be t the same time.....soooooooooo, yes you did contradict yourself.
Can you talk me through this?
His argument appears to be that the universe was not that at one time, and then was there at a later
time, and not that both cases were true at "the same time
" as you appear to be saying. Can you cope with the idea of a house not being there, and then getting built, and then it is there? There is no contradiction because being there and not being there occur at different times.