depends on how long you have had it. If its within their 2 week grace period you can probably just bring it back to the store and say you want a new one.

If it has been more than 2 weeks you will have to call T-Mobile and do a warranty exchange. Shouldnt cost anything if you can show that it was a manufacturing error. But to get just that little piece replaced is not likely, nor would you want to try it yourself. They will simply send you a new phone.

 

does it hinder the camera performance? If not i'd just carry on.