If you want to import EML to Office 365 then, I would like to suggest a third-party EML to Office 365 migration tool. This tool easily exports EML files into Office 365 mailboxes. Here I introduce ShovivEML to Office 365 tool, which is capable to migrate EML files into Office 365 as well as migrate EML files into the Live Exchange server. The tool provides three different licensing such as Personal license, Standard license, and Technical license.
Well, before buying the tool, you also try its free trial version that exports the first 50 items/folder as well.