Carriers are about to hire them. Tell them what actually happened — under your name or anonymously. Free, no account needed, and the driver can read your account and respond to it.
This names a real person and can cost them work, so write only what you know first-hand or can show. Reports are shown to carriers as unverified and count towards no rating or score. Your email address is used once, to confirm it is yours, and is never published.