Before RMA (claim), the devices should go through ERMA process. The ERMA result will decide either it is valid for RMA or not.
However, before we agree for ERMA, I need to understand more about your issue. Can you help to provide some failure details ;
1. What is the failure rate? What is the failure rate vs. tested sample? Example: 15 out of 100 units.
2. What is the failure symptom? Please elaborate the failure symptom in detail.
3. How did you determine the failure? Please elaborate the procedures.