Why can't I make or receive phone calls, receive or send texts??

I have an iPhone with sprint, and it has worked more than amazingly prior to this. It wasn't until last night around 12am that this started. I have had the phone for 4 to 5 months now. The bars in the top left are flat and occasionally one will pop up. I can t make calls and texts are slow to or just don't send at all. I was messing around on my download app in the browser and it closed and then thu problem arises. I have deleted the app even turned on and off my phone several times and turned airplane mode on and off several times. Please help:/ this is not an issue with location, and everytime I make calls it just says "calling mobile..." please help!:/