Voicemail password pop up

So got the phone 2nd hand and everytime I hang up from a call the "enter voicemail password"popup pops up. Can I disable this somehow? Went through settings and didnt see anything that might be of assistance. Is that something that the previous owner has to do?

iPhone Voicemail

When this happened to me and my wife, we had to go to AT&T (dial 611) to get them to do whatever they do, then all was back to normal. If you don;t us AT&T, then I really don't know what to do.

By the way, when you need AT&T **OR** Apple assistance with issues, just call 611. Its free too!