I buy Samsung note 9 2 days before from other person means its not a new one, after getting I noticed that there is no software update option in about devices, and secondly, my Samsung pay is giving me the error of modification in the software. I am also unable to connect with Samsung kies. Samsung kies says that unable to connect however its connecting Samsung DEx, please help me with it I am very worried. its Note 9 f,DS 128 gb
Download this app from the play store:
Under knox warranty void do you see
If its different then you have a broken phone that someone has attempted to modify.
If you would like more information about knox i would recommend reading this
Hope this helps to determine what is wrong.