Was it made clear to the Fidelity rep that the excess contribution was the result of an ineligible rollover into the 401(k), not an elective deferral or employer contribution that would have come from the employer? If they can process a regular distribution without the involvement of the employer (which is may or may not be permissible if you are still employed by this employer), it seems like they could process the corrective distribution under these circumstances without the involvement of the employer.
