Brand new 4TG WD Passport won't eject

Hi peeps.

I’ve literally just got my new drive, transfered files over to it… Checked that they were they could see them… Deleted said files of my laptop but now they are no longer on my new hard drive and it wont eject! Not happy if I have just lost ALOT of files… Any suggestions would be greatly appreciated. I’ve got a mac book pro running High Sierra 10.13.3

Thanks in advance