Good day,
I can use a combination of A2Billing, PHP and MySql, to create a customized billing solution for you.
I have both the prerequisites and the experience to complete your project.
My skill set is as follows:
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 media e.g. Asterisk IVR, ffmpeg and sox
Engineered SS7 based Carrier Grade ISDN-T1 cross-connects
Please feel free to contact me at anytime for further information.