Heathrow 09L - Only ever write to the very top, by name, at the registered business address and make it a registered and recorded delivery letter.
Bosses don't like receiving snotty letters of complaint and will pass it straight to the department head, this way your complaint gets dealt with from the top down and not the bottom up! Just make sure of all your facts when writing, tell it like it is, don't embellish anything. Make sure you mention your are a Gold Card holder.
Sir Timothy Charles Clark KBE is the current President of Emirates, I believe,
and you should find him, (or his PA), at: Emirates Group HQ, PO Box 686. Dubai, UAE.