Yongnuousa.net only warranties items purchased on our site.  For warranty service or other questions on items purchased elsewhere (amazon, eBay, b/h. adorama etc),  you must contact that seller or contact Yongnuo directly. 

Their email address is Service@hkyongnuo.com

If you have a question about an order that originated on www.yongnuousa.net, you can email us at tpaynephotography@att.net