luggage return from Shenzhen Shekou to HKIA

Hello
My son has bought a ferry ticket for Shekou at HKIA, but then he mistakenly crossed the HK border and could not go back into the international zone to take the ferry. The problem is that his luggage has taken the ferry without him, then Shekou officials told me they sent back the luggage to HKIA. But I don't know where to claim the luggage now, someone on the phone told me room 6T110 but I cannot find this room in HKIA. Any help would be appreciated. thanks