One Stick Died After Only 3 Months

One of the two sticks of RAM was throwing errors in Windows Memory Diagnostic and crashing the PC after less than 3 months of use. I cannot find the original packaging to send them in for an RMA from G. Skill and am not sure this was a certified resale site, which is a requirement for their warranty use. Now I'm stuck with 8gb RAM.

Verified purchase: Yes | Condition: New