There are some scenarios in which you may want to allow a number to be uploaded multiple times against different names (e.g. a school that needs to contact a parent on one number but referring to two different children in separate messages).
By default, the Web Portal will automatically restrict duplicate numbers from being uploaded; however, this can be changed to allow duplicate numbers to be uploaded
In order to change this setting, you'll need to submit a support request.
To see the current status of this feature (on or off) Go to Account, then Account Settings. The toggle switch will indicate whether the feature is turned on or off.