Can't send SMS from Galaxy s4

Recently I started getting a pop up message when when I try to send a text from my phone.

"Free Msg: Your Text to Landline msg is waiting to be delivered. Reply Y to deliver your Text to Landline msg and opt-in. Msgs billed at $.25"

Not sure why I am getting this or how to remove the problem. I have tried reset and restore to factory, but that doesn't seem to help.

Thank you

 

sprint is my carrier

Thanks for your reply

 

Update on this issue. It seems to have worked itself out. All of a sudden the text start going through.
Go figure

 

Thanks so much for your help and quick reply!!