Phone Call Recorder - ACR is "free." It trumpets that all call recordings, incoming or outgoing, even photo calls—meaning FaceTime calls—are unlimited in length. But that's if you upgrade via in-app purchase to the pro version for $59.99.
10Hello, this is [your name]. I’m probably at home just avoiding someone I dislike. A funny way of telling someone you’re avoiding them without sounding offensive or having to pick their calls. Please speak very slowly, make it short, make it sweet, and I’ll deliver the message to them. Using other household appliances as stand-ins for the message center is cute and funny. This voicemail will warn callers not to bring drama, so you can save yourself the trouble of having to hear a message that was about to spoil your day.

If you recently restored or updated your iPhone, your network setting may have been affected and may be causing “iPhone voicemail error try again later.” Please reset your network settings. Go to Settings > General > Reset > Reset Network Settings Enter your password. Press Reset network setting in red font. The phone will automatically reset it. After it restarts, your phone then tries voicemail again.
Once the voicemail is done, click the "Stop" button at the bottom part of the tool. You can find the recorded audio by clicking the three parallel bars at the right bottom of the recorder. From there, select the recording track and click the "Play" button to listen to the recorded voicemail. You can also click the "Folder" icon at the rightmost part of the Recording List section to open its output folder.