Is your phone on airplane mode?
did you try turning your hpone off and on.
how is your reception.
Do a mock test with a phone that is right next to yours. If it doesnt go through call sprint.
Check chomp. if you turned off the notifictions for text messages when one comes in it wont notify you one came. C if the message came in but u just didnt notice it....
and lastly..... did you pay your bill? Knowing sprint if you didnt they could start turning features off till you do
hope this helps