Those who deny consciousness, generally do so in the name of a science/empirical epistemological framework. This is a self-contradictory view.
In science, and it parent methodological naturalism, evidence is king. Evidence takes precedence over theory, and theories which conflict with evidence are to be tossed, not the evidence.
The most clear-cut of the Delusionist texts I have found is Blackmore's A Very Short Introduction to Consciousness. In it, she cites a variety of experiments on consciousness, that refute every materialist theory of mind that have been conceived. She also assumes that physics has proven materialism to be true, which then leaves her in a quandary. The way out she seizes is that many of the psych experiments she cites, not only bring materialist consciousness into question, they also bring the validity of our direct experience of consciousness into question as well. Her evidence for this second point is solid -- our internal understanding of our experiences can be and is sometimes in significant error.
So -- Blackmore's argument -- materialism is true, materialism cannot explain consciousness, and we are often confused about consciousness, therefore consciousness is not real -- is actually a credible piece of reasoning.
There are three serious problems with it. 1) Conscious experience is MORE fundamental as a datum than any other evidence we ever have. Dismissing the source of all data -- vitiates the entire data-based methodology that the delusionists supposedly ascribe to. 2) Delusionists must come up with a highly credible explanation for why we would have developed a delusion of consciousness. The first such suggestion was from Julien Jaynes, and he proposed consciousness was a parasitic memeplex that infected our brain hardware ~2000 BC, displacing a prior bi-cameral mind operating system. These explanations come across -- not as highly credible -- but as kooky conspiracy theory rantings ... David Chalmers considers this to be a major shortcoming of delusionists, and has dedicated an upcoming volume of the Journal of Consciousness Studies to this subject: https://philevents.org/event/show/64626
3) The initial assumption by Blackmore -- that materialism has been proven, is false. Materialism has actually been DISPROVEN. Energy has been shown to be more fundamental than matter, and information is an independent feature of the universe from both, and math appears to be even more fundamental than any elementary particles (fundamental physics is basically just math), and physics has been shown to be fundamentally open (all laws are only regularities, and are breakable gauge symmetries).
Sooo -- it is not IMPOSSIBE to make a valid case for delusionism relative to consciousness, BUT the cases made to date are woefully insufficient relative to the burden of evidence they carry to repudiate our basic source of data.