Ive read that satan does not exist, but wat about people who are said to be possessed by demons, and why are people suffering?
In The New Path by Swami Kriyananda, Chapter 30, there is a quote of Paramhansa Yogananda as follows:
“I used to think Satan was only a human invention, but now I know, and add my testimony to that of all those who have gone before me, that Satan is a reality. He is a universal, conscious force whose sole aim is to keep all beings bound to the wheel of delusion.”
This is a deep question not easily answered in a few short paragraphs. Swami Kriyananda further explains your question in this book and I hope that you will purchase a copy to help you on your path.
In the same chapter he goes on to state,
“Man only tunes into, and expresses, limited aspects of consciousness.
“His thoughts are never solitary cries flung into a cosmic void. Like birds, rather, riding on a wind, his thoughts are supported, and further influenced, by whatever stream of consciousness they enter.
“Depending on which aspects of cosmic reality man himself tunes in to, he is drawn downward or upward in his spiritual evolution — down toward matter by what is known as the satanic force [ie demons], or up toward infinity by God’s love.
“It all comes back to the individual, his perceptions and his karma. He can choose the light or darkness. He can find God.”
Joy to you, Seva