Maybe if you live in Alaska and drive it all year long, or in the desert and leave it exposed to the elements, I could "possibly" understand that happening, otherwise, sounds like a defect to me.

 

Talk to your salesperson, General Manager of the dealership. If you are still within the 3yr/36000 warranty, and your dealer still refuses, contact the GM Rep in your area. If that doesn't get you anywhere, then contact GM directly. You can also try another Chevy dealer in your area if you have one. 

 

Honestly though, sounds like you need a new dealer.

 

Good luck, but don't give up because some service writer told you it wasn't covered.

 

The same manufacturer will no longer replace dials/knobs under warranty, due to worn lettering / numbering ... without first *smelling* the item in question.  If there is ANY aroma, the manufacturer will not replace the part.  It would seem as though some people with improper cleaning agents have been wreaking havoc on radio control knobs (etc).  We had a similar situation in my wife's (out of warranty) car.  The radio control buttons on the steering wheel have become slightly tacky.  At first, we thought it was body oils ... but that was ruled out when it could not be cleaned.  It seems like it is some sort of long term reaction to a specific cleaning agent.