I had the same problem! I made the mistake of getting this app on my phone. It was called phone fusion. It was for visual voicemail. Well, even though I deleted the app from my phone, my voicemails were getting forwarded to an online account, but because I set it up wrong, the voicemails were not even going to the online account. Callers were getting the same message. So, I called Sprint from another phone and they were able to reset the voicemail back that came with the phone. They can do it, they just have to do it and then you must power off your phone and turn it back on. They had some trouble with mine at first until the Sprint person figured out that after they reset the phone back to the original voicemail that came with the phone, you have to power off and back on. They had to reset mine twice before it worked. So, call back and tell them to try again and be sure to power off after they reset it. It might work!
