Block Unwanted Calls
If your Direct Line number is getting spam calls more often than you would like to from a particular number, you can add the number to block list. Follow the steps below. Settings > Blacklist > Enter the number in the box > Block. (Screenshots below - Open image to view in full size).
Anonymous Calls: Anonymous calls are blocked by default. Otherwise, click the Unblock icon besides the Status.
Import from Recent Calls: View records of calls that were made to your Direct Line > select the numbers you wish to Block > then click Import.