In U2000 version V100R002C01SPC004, If you want to delete a fiber/cable, you go to the menu, select the fiber/cable and click in "Delete", the operation returns a message telling operation succeed, but you will be able to check that the fiber/cable remains in the menu.
If you try to search the fiber/cable in the Main Topology you will receive a Message telling: " The object is not found, The object does not exist".
If you try to create a new fiber/cable using this resource you will not be able because really the fiber/cable has not been deleted.
If you can not delete a fiber/trail (although you receive a succeed message) and U2000 version is V100R002C01SPC004 you will have to install a new U2000 version to fix this bug.
This is a U2000 SW bug that is solved in further version like:
U2000V1R2C01SPC501 version and further solved this bug.