voicemail retrieval?

Hey, @magenta4962977​! I am so sorry to be the bearer of this news, but T-Mobile doesn't have a way to recover a voicemail once it's deleted. For pay in advance plans, played voicemail are stored for 14 days but need to be re-saved to keep in the system (un-played voicemail are stored for longer to give you an opportunity to hear them). I know it won't help for the message that's lost, but if you have an Android phone with the Visual Voicemail app, or an iPhone with the voicemail feature it comes with activated, there are some ways to save your voicemail listed here: How to use voicemail​!