Modest proposal
No details, but is there a presently legal way to use the methods of robocalling to -cost- the phone companies money? Which should encourage them to stop it.
For instance, either disable customers' service by some kind of robocall trick, leading to complaints and compensation (nb: probably very illegal); talk people into pressing some buttons to reconfigure or cancel the service from their end; or, sell customers a different company's telephone service, or Skype or something.
It may be illegal even to have these thoughts.