How do I get help with a defective set of Beats Solo3 wireless

I purchased Beats Solo 3 wireless on-ear headphones and only 1 ear works, I think this must be a defective set, and want to know how to get them FIXED or REPLACED,at NO CHARGE they were purchased on Aug 22,2018 so they are only 8 1/2 months old. Sounds like a Bad Product !!!!!!!