No new matter can be formed
You wrong there. Matter is formed all the time. If this was not the case the universe would not be expanding.
There's no "new" matter. All matter is here since the beginning of times when it was heavily dense before it started expanding.
New matter creation would contradict the Conservation Laws.
What about Einsteins law? hmmm now it gets interesting. Surely you can get mass from energy? Or does it only work the one way round?
Dude ... watch the videos by minutephysics or if you have a degree in theoretical physics I will shut up