Well, this may not get you anywhere but Phonak (this is disguised as Sonova which was all Phonak before they decided to segment companies for liability purposes and cost centers) North America Home office for Phonak is West of Chicago in Warrenville, IL But they also built a repair center and hardware creation-issues in nearby Aurora, IL. The phone number for that is (630) 821-5000.
These are really Phonak Lumity aids. Give the number a call, but they will probably send you back to Costco, who will then send them right there anyway. Sorry about the drive. They should be under 3 year warranty.
If my golf ball driver was good enough, I could have broken a window hitting across the highway at my old office, so I know where both are - no secret to anyone. lol