Step 1: Go to the TMS URL: 

Step 2: Choose the correct account

Step 3: Click on the Dialing Restrictions menu item.

Step 4: Click on the Block List sub-menu item.

Step 5: Click on the “Add Block List Item” button.

Step 6: In the field available, use the prefix followed by a * to block all numbers in that range.

For example, to block all 082 numbers, you may dial 082*

Step 7: Click “Apply” to save.