I have my uncle’s recording of him singing me ‘Happy Birthday’ on my phone recorder which I’ve saved since June 2016 which apparently cannot be recorded other than via speaker phone to a recorder that makes a poor quality recording. So I seem to be unable to delete it if I want to hear it again so my message machine fills up continuously. My phone is ATT. Is there any way for me to record it to save his voice to some other media so I can replay it to hear him again?(both he and my dad,his brother passed away). Are there any home phone systems available that either record to a removeable chip, cassette, or whatever which can be saved other than an audio recording to another audio recorder which declines its quality significantly?
Please note that Apple Visual Voicemail uses a very small amount of data from your data allowance - typically around a maximum of 85KB for a 30 second message.

If your carrier supports the iPhone voicemail feature, you can retrieve and listen to your voicemail right from within the “Phone” app and call your contacts back by simply tapping their messages. That type of functionality is pretty neat and useful, because it saves you actual time. If not supported by your carrier, you will not be able to see the visual overview of your voicemail inbox and use any of the related features. Tapping the “Voicemail” tab in your “Phone” app will simply call the number associated with your voicemail box. So let’s get going with creating our custom voicemail greeting on iPhone! How to record your own Voicemail on iPhone Phone → Voicemail → Greeting → Custom → Record → Save
Most people screen their phone calls and often avoid answering unknown numbers. If you’re applying for new positions, you should try to view each unexpected call as an exciting opportunity! In the event that you simply can’t pick up the phone, you’ll want a polished voicemail greeting to let the caller know they’ve reached the right person.