M&P - Smith and Wesson Customer Service
I've had my M&P 9c for a while now. It came with two magazines, one with a flat buttplate and one with an extension for your pinky. I couldn't quite get used to the flat buttplate so I called S&W. I talked to a really nice guy in customer service and was off the phone in 3 minutes. They are sending me a new buttplate free of charge...cool!
So just a heads up to anyone with the same problem, give them a call and you'll probably get the same treatment. Great customer service on this.