While missed calls aren’t ideal, you can let your caller know you’re still there for them by having a great voicemail greeting. The best business voicemail greetings let your customers (and potential customers) know why you’re not available and how they can best get in contact with your business. They are also short and to the point. You usually want to keep your greeting between 6 and 24 seconds long so callers don’t hang up halfway through.
• In the future, you can reactivate by sending an SMS with the keyword VVMON to 8860.

If resetting your Networks Settings doesn't work, the Apple forums suggest enabling Airplane mode for 30 seconds to return to Visual Voicemail. I have personally experienced the "Call Voicemail" issue every time I have updated to the newest iOS 11 beta and reboot my phone. After two attempts, the Airplane suggestion worked and returned my Voicemail back to normal, where I can read a transcript or listen to an individual voicemail directly from my iPhone. Here's how to quickly enable and disable Airplane mode: Swipe up from the bottom of your display anywhere on the Home screen. Tap the airplane icon. Wait 30 seconds then tap the airplane icon again.
Of the many things your phone can do, automatically recording a phone call is not one of them. Perhaps not including that feature is a security precaution for phone makers; it could be a potential liability issue. Regardless, from time to time, documenting a call is a useful thing to do, whether you’re conducting a phone interview or cataloging a customer service call.