I recently purchased the JB Wholesale xpen (I thought it would be a good way to ease Gossy into having the run of the house when I'm gone) and was a bit disappointed. I only ordered the 36 inch one and the free shipping doesn't apply JSYK. What I was really disappointed in was the latches on the door - they are not at all secure. It was really easy to push against the door a couple of times and they come free.
Sorry to hear that. Maybe you can use those "spring clips
(don't know what you call them but they came with mine) to secure the door? I got the Midwest one that kiroja suggested and the door seems reasonably secure.