If you have already tried resetting these headphones and that didn't help, the next step would depend on, whether or not, you purchase them directly from Apple or an Apple Authorized Reseller within the last 14 days.
If you did, then you can return them for either a full refund or a replacement pair.
If not, then I suggest that you contact Apple Support directly for further assistance with this matter. To do so, simply select the "Support" link on the lower left-hand side of this forum's web page. Alternately, you can use this link: Beats Repair & Service - Apple Support