Are you willing to make international users pay up to 80¢ per verification? If someone cancels a call, I still have to pay for one minute (it&#x27;s only free if I cancel the call). So if I were to call any American number that hung up on me, I have to pay 80¢ (USD dollar cents of course).<p>Just pay the 0.02¢ or whatever phone services charge these days. If your business is actually big enough to have to worry about phone verification, do it right. Users don&#x27;t like to call your number since they don&#x27;t know the costs associated with it (especially international users). 
Furthermore, it makes number spoofing much harder.