Do you believe that it is possible for us to be saved and for failures in our life to be the result of demonic activity? Looking back over my life, I have experienced one failure on top of another in my career, my relationships, and finances. While I have had some success for brief periods of time, my overall assessment would be I am a failure in life. Am I somehow allowing demons to control me?
Rather than look for demonic oppression as the cause of the failures you describe, it might be more productive to first consider whether your unsuccessful life to date has been due to making your own determinations instead of seeking the Lord’s direction for your life. I know that for many years this was true in my case.
Romans 12:1-2 tells us to make our whole life a spiritual act of worship to the Lord. We’re told not to conform to the pattern of this world but to be transformed by the renewing of our mind. By doing this we can discover God’s will for our life and finally achieve fulfillment.