No signal but I can text.

I just purchased a ZTE max duo a few days ago and I didn't have any problems until yesterday. I got a notification that I had a voice mail but I didn't have a signal to call. I had my daughter call me from her phone and it rang on her end then to voice mail. My phone never rang. I can still text and go online. Is there a signal problem in my area? I really need to be able to use my phone to make calls.