Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
That problem must be quite fustrating. I hope I can help with it.
There are two approaches to take here, I think (unless you can think of another to pursue.)
One, is to assume the phone itself has a defect, and try to fix it.
The other, is to assume the phone service might be at fault somehow. Errors do happen, what with the cellular phone network being somewhat complicated and involving so many components.
The first approach requires that I know what maker and model of phone it is, please.
The second would suggest that you contact your service provider (using another phone, unless 1-800 numbers work, of course) and ask about the status of your account, and report the problem too.