arguing against a deductive argument

"There are only two ways to refute a deductive argument: show one of the premises to be false, or show that the conclusion does not follow from the premises. If you wish to refute my argument, then you need to do one of those two things." Bryan Cross

 http://www.calledtocommunion.com/2009/09/why-protestantism-has-no-visible-catholic-church/