VoiceMail Full (Verizon) from blocked robocalls

I discovered the root cause of my iphone telling me that my voicemail was 100% full, even though I had deleted all of my voicemails and cleared the deleted messages list. After following the instructions from https://discussions.apple.com/thread/250328918?login=true, I discovered that Verizon had retained a year's worth of voicemails from a robocall number that I had blocked. This is a real pain as it takes long time to remove 60 voicemails using the Verizon voice prompts. Is there a way you can block a number AND prevent that number from leaving a voicemail?