Twilio is a very legit business, but any business offering phone numbers that can be automated is going to be at risk of this sort of activity and it's up to twilio to deal with that. However if the FCC can really block twilio from operating in just a 48 hour window that will have absolutely massive impact on businesses of all sizes that rely on it. Not that those companies couldn't find alternative solutions, but imagine just not being able to contact e.g. your banks phone support because the bank has no time to make that change.