Hello!
I have a good experience with sipsorcery platform & a lot of VoIP providers. Also have done setup installation of some VoIP pap modems and VoIP windows clients. The things I need from you is only the VoIP SIP server, the username & password, and also proxy server if exists. I'm available anytime for you, and I can finish this job very quickly via TeamViewer (if there aren't problems with network connection, or firewall exceptions)
I believe it will be a bit hard for you to believe me, but I'm new at freelancer, and of course there is always "for first time" I believe you have understanding.
Thank you for understanding,
Bojan G.