Voicemail not working

I've had three phones, one iPhone 5, one iPhone 6, and now an iPhone XR. I've had the same problem on all phones, where I would go on the voicemail screen, and instead of seeing set up voicemail (i've never set one up before) I only see Call Voicemail. I've tried doing the airplane mode thing, and i've tried reseting the phone many times, but still no luck. When I look it up, no one has had this problem (or no one has talked about it). If you've had this problem before, or have a solution to this problem, please let me know. Thanks!