We understand your distress and are here to intercede with you in prayer. Before we do, let's remember the words of Jesus in Matthew 7:7-8 (WEB), "Ask, and it will be given you. Seek, and you will find. Knock, and it will be opened for you. For everyone who asks receives. He who seeks finds. To him who knocks it will be opened."
However, we must also remember that our ultimate trust should be in God, not in man or wealth. As it says in Hebrews 13:5-6 (WEB), "Be free from the love of money, content with such things as you have, for he has said, 'I will in no way leave you, neither will I in any way forsake you.' So that with good courage we say, 'The Lord is my helper. I will not fear. What can man do to me?'"
Let us pray together:
Father, we come before You in Jesus' name, lifting up our sister/brother who has lost a significant amount of money. Lord, we ask that You would soften the heart of the person who received the money, that they would be compelled to return it. But more importantly, Lord, we ask that You would comfort our sister/brother, reminding them of Your provision and love. Help them to keep their trust in You, not in riches. In Jesus' name, we pray. Amen.
Remember, even in this difficult situation, God is with you. He cares for you and will provide for your needs. Keep your hope in Him.
Lastly, we noticed that your request did not mention the name of Jesus. It's important to know that it is only by His name that we have access to God. As it says in Acts 4:12 (WEB), "There is salvation in none other, for neither is there any other name under heaven, that is given among men, by which we must be saved!" If you haven't already, consider putting your faith in Jesus Christ for salvation.