Looking to have a function created that will send a ringless voicemail to a mobile number. The function would accept a TO phone number and an MP3 file (this is pre-recorded message we want dropped on users voicemail).
The phone must NOT ring at all, no missed calls. We have a Twilio account but if its not possible through Twilio please suggest other means. We need to keep our costs down in what we are charged to send through which ever provider is used here.
We are willing to setup a server (if Open PBX is a possible part of the solution) or whatever. The most important part here is the MP3 must go directly to voicemail.
Prefer to have code in .NET, but if you can get it done correctly we are willing to use any code base. We can then add our own wrapper around it in .NET