You may want to block certain numbers from calling if the number has been identified as spam or if you have disruptive Customers. You can't completely block a Customer from calling, but there are ways to minimize their impact and reduce the chance of their calls coming through.
Before you start
Before you start, please ensure your IVR has the following two nodes:
Global IVR Variable – List of numbers to block

Variable Node – Block Check

Below are two options to block certain numbers from calling:
Replace the List of numbers to block node (recommended)
Click
on the top left corner of the screen.
Click Settings.
Under the Channels category, click Voice.
Find the number in question. Under the IVR column, click the linked IVR to open the IVR in edit mode.
Locate and select the existing List of numbers to block (Variable) node.
On the right panel, click the list under Next Node, select Create a new node. From the list of node options, select Phone Number Match.
Configure the Phone Number Match node:
Enter the phone numbers you want to block, in e.164 format (for example, +16505556426) in the Phone Numbers to Match section.
Set Next Node (on Match) to the same blocked-call destination the Variable node, which is likely a “Goodbye” node.

Set Default Next Node to continue the normal call flow for numbers that aren't on the block list. This is likely your Holiday Check node.
Set Error Node to handle any errors during matching. This is also likely your Holiday Check node.
Beyond blocking
The Phone Number Match node isn't limited to blocking. You can use the same node to set up VIP routing, or route any pre-identified list of callers to a specific destination — just point Next Node (on Match) to wherever those callers should go instead.
Click Publish.
Update List of numbers to block using Regex
Click
on the top left corner of the screen.
Click Settings.
Under the Channels category, click Voice.
Find the number in question. Under the IVR column, click the linked IVR to open the IVR in edit mode.
Do not modify the Block Check variable node
For steps 5 and on, make sure you’re only editing the List of numbers to block (Variable) node to add the list of numbers to block.
From the IVR view, look for the List of numbers to block (Variable) node. If it has been renamed, this node may have a different name in your IVR.
Scroll down to the Expression field. Numbers here are actively blocked from entering the IVR.

Enter the numbers you want to block using this format:
Multiple numbers – 6505556426|8885556427|9515554567 (Be sure to add pipe "|" in-between numbers. To insert a pipe symbol (|), press Shift + Backslash on both Mac and Windows US keyboards.)
Single number – 6504756426
When it is a US or Canadian number (with a code of +1), you can format it with or without the country code. Example: 15555555555 or 5555555555
You will always need the country code if it's an international number.
Leave the field blank if you have no numbers to block.
Do not leave a trailing "|" at the end of the expression — doing so will cause you to accidentally block all phone calls to this IVR.
Click Publish. Enter a short description of the updates you made, then click OK.
Blocking unusual numbers
Note that deciding to block unusual numbers might inadvertently prevent legitimate Customers from reaching you, as they could be using VoIP services.
Use Rules to block email or SMS numbers
You can also use Rules to stop incoming emails or SMSes. See the links below.