Hi there Devin and welcome
Can you tell me what steps you have take to try to solve this please?
Whats the error you get when it fails to send?
ok, can you go to Settings, Applications, swipe to the list All
Then locate Google Services Framework and press clear data
then restart the phone and tell me if it now sends please.
ok, can you go to settings, applications, all, locate messages and press on Clear Cache not data
Then restart the phone and tell me if it now sends please
ok, go to the play store and download handcent sms
Open it and tell me if with that you can text please
ok, we will have to reset the phone, it will remove all your data so backup any data first before doing this.
Then go to Settings, Backup and Reset
Then choose Factory Reset.
Once done, setup the phone again like when you first received it.
Tell me if it then sends.