My sent text messages on my Nokia Twist keep disappearing?

This happened with the last Nokia Twist I had and I had to get a new one. My text conversations are in a list and the outgoing texts that I send at in yellow and the incoming ones are in white. Well every time I send a text, my send text disappears from the list. The message still sends but I can't see it. It's very frustrating! Is there anyway I can fix this or should I just say screw it and send it back and get a different phone? I've only had it for about 2 weeks now.My sent text messages on my Nokia Twist keep disappearing?
Just to tell you right off the bat, nokia sucks. And you might be out of room in your text inbox/outbox. There is normally on every phone an auto delete feature in the settings that deletes an old sent text or an old received text. You can turn that off but be warned, your inbox might get full alot!