If its the one that I'm thinking of check your roller placements on the wheels. I have the one with the measurement grid top and the two sides fold down; on a black frame. There are two different sets of wheels; one set is for the part that swings out and the other is for the center. Ask me how I know; mine is so wobbly unless it has at least one side up. I will eventually get in there and put the wheels on the right way but it works for now. I do like it alot so I'd fix the wheels before taking it back too.