If I say 'yes', or you going to believe me? And, if I say 'no'. then are you going to disbelieve me? In both the type of answers, it is not going to make much of a difference in the way you lead your life! Right? Therefore, what does it mean? It is all in our perception of things.
Here, the problem is that since you cannot see or feel that so called 'alternate or parallel universe', you cannot say that it does not exist. There are lots and lots of mysteries and wonders in this world that are beyond our understanding. Simply because we do not understand, we cannot say that a particular thing or matter does not exist.