Yes! You can! You can find the FTP credentials on your Live365 Dashboard.
Please remember when Uploading via FTP that your files have to be in a mp3 or m4a extension. Please try not to use unique or unconventional characters in file names when uploading files (б,ч,숭,이,ç,ñ).
You can read example step-by-step instructions on how to upload via FTP using Filezilla here.