My iphone 5s wont send or recieve texts or make or get calls!

Okay, so i have recently got my iphone 5s, nothing has been wrong with it. I was at a friends house and woke up and had a text from my grandma talking about my phone bill. She said " reset your phone and let it sit for 5 minutes and turn it back on and your phone should be working " so i thought maybe she just turned my internet off or switched some of my settings around. Well, i tried texting her back and it wasnt going through, so i tried calling her it wasnt going through either. Therefore, i got on here and tried all the methods, the home + lock buttons, reseting my entire phone, turning it on and off, airplane mode. I just didnt know if anyone was having the same problem or has any solutions to what might be wrong. thanks.