I had to contact Anker support once for my Soundbuds Slim, which are my first bluetooth earbuds, and the battery was horrible. It would go from 100 to 60 pretty fast, then stay at 60 for a long time and once it drop to 40, it quickly died. Contacted Anker within a week of purchase and a couple emails later, I was told to use the return label to ship my earbuds to get a replacement within a week. The new (replacement) earbuds are great and I have no problem.
At first I wasn't sure what to expect from the support team but was very shocked and surprised to see such great service!! Keep up the great work Anker!!