title: How to block a number in Twilio
body: <p>Problem statement:
  A user comes to our web site and checks the check box to 'Un-Subscribe'.
  Our system will remove corresponding cell phone number from our subscribers list.</p>
  
  <p>But We want to make sure that twilio should also block that number. For this:</p>
  
  <p>Q1: How can we ask twilio to block those number(s) using C# code; so that; if  by mistake we send SMS to this number; the SMS get blocked at twilio end at least.
  Q2: In case we successfully blocked the number at twilio; How could we unblock those blocked number(s) at twilio, in future  using C#.</p>
  
  <p>Thanks,
  Saurabh</p>