I don't think Best Buy will do anything to fix a physically damaged product. You can call the store and speak to the Geek Squad department took confirm, but I would contact the Beats headphone manufacturer.
Unfortunately that device was not meant to be repaired so it's not like that you'll be able to repair it easily. If you could send pictures of the damage or go into an electronics repair store, I'm sure they'd be happy to give you an estimate. It is however rare to find headphone repair outside of specialized people that offer their services individually. I don't believe that most electronics stores offer a repair of that sort.
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