That is terrible! I cannot imagine how angry you must be! How in the heck can someone do this to someone else's property? I hope the police catch them in the act. Does the garage have survelliance camera? If so, maybe they could figure out who did this.
I hate to tell you this, but my son's car was hit recently and the right exterior mirror was knocked off. It cost us $225 to replace that one mirror. Car repairs are so outrageous.
Hope you get it fixed soon---and can find a safer place to park. Thank goodness they didn't attack you too!