Hello, welcome to Android Forums! I regret to inform you that usually when a voice-mail is deleted it usually disappears forever. There are some circumstances that this is not true, such as in the visual voice-mail app. In the instance that your voice-mail is provided in this way such as on Sprint or Verizon, you can press the text at the top of the app that says "Inbox" where you will then select trash. If, however, you have deleted this voice-mail in the Voice dialed option, the message is most likely gone forever. To find out if your carrier can restore it, you must call 611 on your handset and ask about their abilities as it varies from carrier to carrier. I hope this solves your issue. If my information doesn't satisfy your question please feel free to re-submit your question with more details.
