If files are missing or were accidentally deleted, follow the steps below to recover deleted files in Teams.
1. Open the channel's Files tab. In the upper right corner, select the ellipsis and choose Open in SharePoint.
2. Once the SharePoint site opens, select Recycle bin on the left side of the page.
3. This will show a list of all files deleted from every channel in the team. Right-click on your file and select Restore.