We are deeply concerned about the spiritual attack your niece is experiencing. It is important to remember that our struggle is not against flesh and blood, but against the rulers, against the authorities, against the world rulers of this darkness, and against the spiritual forces of wickedness in the heavenly places (Ephesians 6:12, WEB).
Firstly, we must ensure that your niece has accepted Jesus Christ as her personal Savior. It is only through His name that we have authority over the enemy (John 14:13-14, WEB). If she hasn't, we encourage her to confess with her mouth that Jesus is Lord, and believe in her heart that God raised him from the dead, for it is with the heart that one believes unto righteousness, and with the mouth that one confesses unto salvation (Romans 10:9-10, WEB).
Now, let us pray together for your niece:
"Dear Heavenly Father, we come before You in the mighty name of Jesus Christ. We plead the blood of Jesus over [niece's name] and her situation. We rebuke and bind the spirit that has been attacking her, in Jesus' name. We command it to stop speaking her thoughts, to stop following her, and to stop revealing her private life. We loose her from the bonds of depression, shame, and hallucinations, in Jesus' name.
Father, we ask that You fill [niece's name] with Your Holy Spirit. Strengthen her faith and give her the courage to resist the devil, so that he will flee from her (James 4:7, WEB). Help her to put on the whole armor of God, so that she may be able to stand against the wiles of the devil (Ephesians 6:11, WEB).
Now, [niece's name], we guide you to renounce any agreements made with this spirit, knowingly or unknowingly. Pray this with us:
'In the name of Jesus Christ, I renounce any and all agreements made with the spirit that has been attacking me. I cancel any permissions or access I may have given it. I choose to submit myself to God and resist the devil. Greater is He that is in me, than he that is in the world (1 John 4:4, WEB). Amen.'
Father, we thank You for Your love and protection. We trust that [niece's name] will walk in freedom and victory, in Jesus' name. Amen."
Continue to stand strong in faith, encouraging your niece to read the Word of God, pray, and worship Him. Remind her that God has not given us a spirit of fear, but of power, love, and self-control (2 Timothy 1:7, WEB). We are here to support and pray with you both.
Let's join Flaywell in a resounding "In Christ Jesus Name"! Trusting God's power and presence. "For where two or three gather in my name, there am I with them" (Matt. 18:20). Keep praying and believing, everyone! 
for mental strength & protection. "For God has not given us a spirit of fear, but of power and of love and of a sound mind" (2 Tim. 1:7). Trusting God's shield. In Jesus' Name! 
Let's lift up 
