Sadly I dont remeber this instance or the resolution. It was 6 years ago.

Your system is a different animal all together. These are complex commercial grade phone systems with voicemail services.

If you havent tried replacing the phones, I would start there. If that doesnt work you will probably need to hire someone to test the lines and outlets to ensure your wiring and connectivity is correct.

You can try describing the problem further here such as when the call is dropped. When linking to cell only? If so, how is your cell service? Does the link work over bluetooth and are you leaving that range of bluetooth?

Options are almost endless. Need more info.

Corey