how to prevent change in file owner/group on centos when using sftp Filezilla to upload to server

All files on centos are owned by me, goofy/domain. Uploading a plugin to the server using Filezilla caused one of the files to appear on server as apache/apache rather than goofy/domain. How/Why does this happen? How to prevent this from happening? Now that it has happened and I no longer am able to delete the file, what can I do to delete it?