I had problems with the I/O panel with a Cooler Master Storm Sniper. I called their customer service and they sent me a new one in three days. They didn't even want me to return the faulty one.
You can also browse thru their web site and find the parts store. Narrow it down to your particular case and they will have the parts that are available listed with the prices. I'm sure you can get one there if your case is out of warranty.