One of my contacts' text messages aren't showing up. i think ive done something to their personal settings..

the only time i can see i have a message from them is when its on my task bar at the very top of my screen. and the only time i can see my conversation with that person, is when i manually click their name and type a message to them and when sent i can see our convo. but it doesnt show anything while im in my inbox.

does anyone know how to fix this?

I use go sms app, not the regular text messaging that the phone came with.