Installation of VOIP Softswitch, Billing System, .etc

General information for the business: We are fairly new to VOIP
Industry: Technology
Kind of support: Software
Description of support work: Require assistance and advise on which tools are effective for our business goals and installation as well.

Please go through our list:-

http://www.asterisk2billing.org/
https://www.pyfreebilling.com/
http://www.astppbilling.org/#
https://billrun.com/

http://www.asterisk.org/
http://www.opensip.org
http://www.kamailio.org/
http://www.iptel.org/sems
http://pbxui.com/
http://www.freeswitch.org/
http://www.2600hz.org/
http://www.sipwise.com/
https://www.opensips.org/
https://www.bicomsystems.com/products/telcoware-server-edition

https://www.programmableweb.com/api/rebtel-voice-platform

please add API into our platform
Extra notes: