The "it's just a theory" comment shows that you don't really understand how science works. Theories are not just hypotheses, they are hypotheses that have been corroborated by research and we take them to be true, UNLESS, proven wrong. Although this happens occasionally, theories are to be taken to be fact for the time being. Instead of saying "it is just a theory" you need to get to work and do the research that proves it wrong. Short of you doing that, quipping platitudes does nothing to convince anyone.
This disingenuous answer sounds awfully similar to the response creationists give to the theory of evolution. Are you also a creationist?