I used vicidial / asterisk for voicemail and its not detecting everytime caller hangup.
GIving you a view of the setup, calls come from local PSTN to PBX BOX then going to our asterisk server (vicidial) which is connected through Digium Card (Sangoma).
Asterisk recognizes incoming calls and takes voicemail then forwarding it to email properly, however if the caller does not press '#' or hash key and hangs up directly, asterisk continues to record voicemail until certain time it hangs up. Basically, we need hangup detection for this.
please let me know if you can do this quick on teamviewer.
add me on skype