incoming/outgoing calling is not working...

I dont know what happened like I might have changed a setting to turn off my actual phone calling and receiving calls, but when i dial out it never makes a ringing?dialing tone and after a few seconds it makes a beep and says "no signal." When someone calls my phone, it just rings three times and goes to voicemail on their end, and does nothing on my end. But my texts work fine and internet access is still working so is it possible I changed a setting on my phone that controls the calling? Anyone? Please and thank you.