Ask HN: How do I get started building phone menus programmatically?

I want to build a web application that one can control using a phone menu. I have built a web player where one can create playlists. Now, I want users to be able to dial a phone number and be presented with a list of their playlists. For example: "Press 1, for Playlist 1" "Press 2, for Playlist 2" etc Then after that selection and when a playlist is playing, buttons "3" and "5" would be "Back" and "Next". I have never built these kinds of menus before, but I would like to start. I am targeting emerging markets, and I have contacted Twilio (numbers, toll free numbers etc) and they told me they do not offer their services in those countries. I would appreciate being pointed to any helpful resources.