Wrong capacity used and fails copying files

I bought a MyPassport 1 Tb a few days ago. I just wanted to copy the content of a 750 Gb disk on it. One of the folders was big and it took a while, but it ended with no errors. When it ended, it did not appear in the MyPassport. I need to refresh the file explorer to see whatever I copy in the MyPassport, but for this folder that didn’t work, it won’t appear. So I copied it again and this time I could see it after the refreshing.
That happened with several folders. Now it says the disk is full and I haven’t copied the half of the source disk. So I guess that those folders that disappeared are there consuming space but somehow you can’t see them.
I run the windows tool to check disk errors but it found nothing.
Do you think there is a problem with the disk and that I should return it?

Hi @Frigate,

Have you opened a Support Case? If not opened, for more information, please contact the WD Technical Support team for the best assistance and troubleshooting: