It is a logical fallacy to say you previously existed. Just as it is saying you exist now.
Phal Osee wrote: I do not exist where I previously existed. Now I exist elswhere. Who I was in my previous existence is no longer the me that now exists in a different form in another location writing this post. In my new existence I come to a new conclusion, that is, that which previously was is now no longer, since time has evolved. Therefore the new reality is that I can now prove I exist in the form of mortal on the same planet as you who read this revelation.