@WooCash, kindly please be informed that as of now, it’s not possible from the system to delete only the media attachments (files) without deleting the entire submissions that hold the media files. So if you wish to delete the media files, you will also need to delete your entire submission.
You should be able to follow our feature request here:
Hopefully, we will be able to make this feature live soon. But until then, you will need to delete your entire submission.
Apologies for the inconvenience caused! 
