I want to turn off the Voice Calls feature on my Plivo number because I only use them for sending SMS through their API. Sometimes when people receive a sms , they call back to the number they see and wait on hold or something for about 45 seconds incurring in unnecessary costs.
Thanks
you should be able to achieve this by removing answer url for the application.
Application
https://manage.plivo.com/app/edit/[application-id]/
Answer URL
This should setup no answering url for your number and hence people cannot call you on this number anymore.