My Phone Carriers is Ok

My phone carrier is At&t. I am a prepaid customer.  It’s tolerable, but I don’t like the point where I must put fifteen dollars on my phone. Perhaps, they could allow someone to put ten dollars on their phone. I don’t use all my minutes, because I don’t like talking to people, so I buy text messages. Though there is a feature where one can buy only text messages, but I’m a bit concerned as if my account says zero dollars will I be able to use those messages? I can ask I suppose. Other than that, At&t is a pretty descent phone carrier service.