2021 Audi E-TRON Sportback

2021 Audi e-tron, 44,749 miles. Right after a scheduled service at Audi [XXX] on XXX, I noticed a loud droning/humming noise from the drivetrain while driving. The noise tracks with vehicle speed - it gets louder and higher-pitched as the car goes faster. I called the dealership to report it as soon as I got the car back in late XXX. Nobody responded. The noise is still present today, roughly five months later, at about 48,000 miles. The symptom matches Audi's own technical service bulletin 2047920 (rev 7), which covers 2020-2025 Audi vehicles including the e-tron: a humming/booming noise while driving whose frequency rises with speed, caused by mechanical damage to the front wheel bearing. Multiple other e-tron owners report the same speed-correlated drone on owner forums, including a bearing failure inside the drive motor and a full rear drive unit failure. I am concerned that a failing drivetrain bearing could degrade suddenly at highway speed. Manufacturer response to date: my phone report right after the April 2026 service got no response. I raised the noise in writing to Audi of America on XXX (their reference XXX). Audi's XXX reply addressed only warranty expiration and pointed me back to the dealer; no inspection or diagnosis of the noise has been offered. A dealer-scheduled service visit is set for XXX. Separate context on dealer handling: in XXX Audi of [XXX] told me to pay out of pocket for covered service while my Audi Care plan was still active (through XXX). An [XXX] service advisor later wrote to Audi regional staff that 'the service may have been eligible for coverage at the time of the visit.' I am asking NHTSA to investigate this as a defect pattern across 2020-2025 e-tron vehicles. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)