It wont let me send out text messages at all,it saves them in my outbox and when I get voicemails it wont let me listen to them.I have no idea whats going on with my phone...
sorry, you must get this a lot but best thing to do is call sprint, when i had this problem with AT&T they said its the SIM/network and they had to do some weird stuff....
go to sprint, do you have insurance? If so they will fix it if it is a technical problem for free. If you have dropped it in water or something like that and have insurance they will make you pay 50 dollars for a new phone.....good luck