IPhone 5c popping out of case?

So I got the iphone 5C… Big mistake. I had to pay full price because my other phone broke and I wasn't eligible for an upgrade for two months. The screen keeps popping out of it's yellow back. The first time, it popped out with my case on it! I picked it up from the table and it looked weird and I noticed the right hand corner had popped out. So I took it into the Sprint store and they said it was covered under Apple's warranty because it was a known problem and that they will send a new phone and that the problem has since been fixed. So, I got my new phone about a month and a half ago. Yesterday the case was on and guess what happened! The replacement has the same problem. Even though I have insurance, they are replacing it under warranty. Has anyone else had this problem?

Oh, that sucks. I don't know a solution, but the other week my phone broke in half with cracks and such and I took it to the sprint store, and they told me to do the framily plan. I didn't pay anything for the phone and now will pay 55$ a month plus, warranty in case it breaks. Odd they didn't tell you about it.