Twilio phone numbers may be called or texted to by outside users, just like any other phone number. To help ensure against calls that aren’t intended for you, whenever a phone number is released by a Twilio customer, we reserve it for a minimum of two months before it can be purchased by another customer so that the former owner can update their records. In addition, we monitor each reserved number until it reaches an acceptably low number of phone calls.
If you are getting unwanted calls from abusive parties, you can use Twilio’s <Reject> verb to create a blacklist and make sure that your project won’t receive nor be charged for on calls from those numbers. Additionally, you can always release your Twilio number and provision a new one to your project. Contact us if you have further questions.