Did you try accessing the My Cloud Dashboard > Shares page and remove the USB drive names that are listed there?
The duplicating USB drive name is a known issue. the solution is to remove the USB drive via the eject option within the Dashboard, then go to the Dashboard > Shares page and remove all USB drive names for the USB drive. Then reinsert the USB drive into the My Cloud, access the Dashboard > Shares page again and rename the USB drive Share name back to the original name.
Here are just a few past threads where this duplicate USB name issue has been discussed:
https://community.wd.com/t/my-safepoints-disappear/160698
https://community.wd.com/t/new-release-firmware-release-04-04-02-105-1-27-2016/148441/68
https://community.wd.com/t/mycloud-creating-numerous-aliases-for-same-drive/160161
https://community.wd.com/t/usb-drive-makes-new-name/152675
https://community.wd.com/t/dublicate-shares-after-reboot/153348
