The Bible gives no model for a soul-sale
Stories about signing away your soul are common in folklore, films, and songs, but Scripture never presents a ritual or contract by which Satan permanently owns a person. God says that every soul belongs to him, which means human lives are not Satan's property to buy or keep (Ezekiel 18:4).
Satan is real, and the Bible takes his evil seriously. Yet he is not God's equal. When he tempted Jesus in the wilderness, he offered worldly power and honour, but Jesus rejected him and worshipped God alone (Matthew 4:8-10). His offers are traps, not deals he has ultimate authority to enforce.
Behold, all souls are mine; as the soul of the father, so also the soul of the son is mine: the soul that sinneth, it shall die.
The devil's chief weapon is deception
Jesus describes the devil as a liar whose falsehood comes from his own character (John 8:44). That helps explain why fear can feel so convincing. A person may have made terrible choices, explored occult practices, spoken rashly, or felt drawn into sin. Those things matter and may need honest repentance, but they do not put someone beyond God's reach.
The New Testament tells believers to resist the devil by submitting themselves to God, and it promises that the devil will flee (James 4:7). The answer is not to search for a secret counter-contract. It is to turn plainly towards God.
Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.
Jesus rescues people who turn to him
Christian hope rests on what Christ has done, not on how clean a person's past looks. Peter denied even knowing Jesus at a moment of fear, yet Jesus prayed for him and later gave him a renewed calling (Luke 22:31-32; John 21:15-17). Failure was real, but it was not Peter's final story.
Peter also wrote that believers are redeemed through the precious blood of Christ, not through something temporary or corruptible (1 Peter 1:18-19). If you are worried that you have gone too far, that concern can be a reason to bring the matter honestly to God. Scripture says that God forgives and cleanses those who confess their sins to him (1 John 1:9).
If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
A simple next step
You do not need perfect words. Tell God the truth about what has happened and ask for his mercy, forgiveness, and help. Trust Jesus rather than the frightening thoughts or promises that may be troubling you. Repentance means turning around, bringing your life back towards God, and Scripture connects it with forgiveness and refreshment from the Lord (Acts 3:19).
It can also help to speak with a mature, trustworthy Christian leader or pastor who will listen calmly and pray with you. If fear is becoming overwhelming or affecting your safety, please tell someone you trust and seek local mental health or crisis support as well. You do not have to carry this alone.