Microsoft Band 2 broken

Hi

I bought a Microsoft Band 2 at Best Buy in Portland when I travel in Feb 26th,2016. And 2 month later when I back to China, the strap was broken without any reason. Now I'm travel to Portland again and will stay for 2 weeks. Can I return it for repairing?How about the procedure of returing for repair and when can I get it. And it is not over 1 year, does the repare for free or not? How much does it cost?

Thank you and waiting for your reply urgently.

Best Regards

Liliom