How do I handle contradicting study results? A foundation of my psychological work is the body. Simply put, I work on a big part with embodiment to diagnose, as well as to intervene and to integrate.

One illustration, or rather one important reasoning for embodiment seems to be the so called facial feedback test. I have read about this test over and over again in literature.

In 2016, there have been efforts to reproduce this test, and these efforts did fail. See here:

https://www.psychologicalscience.org/news/releases/effect-of-facial-expression-on-emotional-state-not-replicated-in-multilab-study.html

All this is rather new to me, so I don't know how to handle this situation. My intention is to do honest work. I am wondering:


Is it careless to still cite the facial feedback although it cannot be reproduced? 
Or is it only careless to still cite if several studies proved it explicitely wrong?
How do I talk to clients about the facial feedback?
Should I simply try it myself and choose to belief what I want?


Please note that I am not asking for opinions. My question finally is:


  As an ethic worker in the field of psychology, how do I handle contradicting study results, based on the example of the facial feedback?


The example of facial feedback implicitely includes a) the contradicting study results and b) the contradiction becomes visible over time.
Short answer
Many individual papers report non-reproducible findings. I would advise you to look for review papers and meta-analysis studies to get the bigger picture. If not available, you can consider to set up a literature study yourself.    

Background
Nature puts it down neatly (emphasis mine):


  Science moves forward by corroboration – when researchers verify others’ results. Science advances faster when people waste less time pursuing false leads. No research paper can ever be considered to be the final word, but there are too many that do not stand up to further study


Recently it has appeared that the results of a great many studies cannot be reproduced, leading to what is referred to now as the "Replication crisis". 

Many factors may contribute, chief among those are according to Nature:


  the increased levels of scrutiny, complexity of experiments and statistics, and pressures on researchers. 


More reliable resources than individual primary research reports are the so-called meta-studies, i.e., review studies that collects as much information there is and where the authors attempt to synthesize the bigger picture to extract solid conclusions from them, as well as confounding factors explaining why some studies may have drawn less correct conclusions.