Simple Solution

1) Pass legislation that makes it illegal for businesses to block or disguise their name/correct phone numbers

2)Set up a set of phone "traps" that monitor for compliance. These would need to be valid numbers that are placed on the "Do not call" list. Current technology will allow the proper number to be determined even if a false one is displayed.

3) Prosecute and collect fines from companies in violation

Seems pretty simple....