I have kind of a wierd/hard to explain problem. I subscribed to Cingular/ATT in Dec. 2006 and was able to send and recieve text messages all the time without having a plan in place (I paid per message). This worked until about September 2007. At this point I could send messages and it would say "message sent" but the desired number would never get the message. The same would happen if a different number sent a message to me. However, I recieved a messasge from ATT when they got my rebate.
I was wondering what I can do to fix this, and preferably, would buying an unlimited texting plan fix this problem?
Best bet would be to call customer service, they can give perform the proper troubleshooting. Sometimes removing a feature and adding it back on can temporarily fix an issue, but if you weren't able to send or receive messages on a pay-per-use basis you most likely won't be able to on the unlimited messaging feature. I suggest you speak to a rep so they can check the settings in the system and on your phone and test it out for you, too. **Make sure to call from another phone with your phone in hand**