Hello,
I can create an IVR based Product delivery CMS/Billing system that suits your needs.
My skill sets are:
expert skill/knowledge in Asterisk PBX, Freeswitch, A2Billing, Kamailio, Elastix and Kazoo
Expert skill/knowledge in SIPml5, Websockets and RESTFUL systems
Expert skill/knowledge in MySql, PHP, Python, C++, Ruby, Erlang
Expert skill/knowledge in Linux OS
Expert skill/knowledge in ffmpeg and sox
Contact me at anytime.