1-2 of 2 Answers
You could try allowing both of them to die, delete them from your bluetooth connections list on your phone, fully charge them to 100 percent, then reconnect them. If that doesn't work, you'll have to replace it. At that point, it would be a hardware issue.
Probably best to just return them unfortunately. I purchased a pair of the refurbished ones and they were terrible compared the the new ones.