I've always said, though I have little respect for the crew of my local GWS (every time I go there I get sold the wrong model, given mad information and/or pressured to check out the latest pre-orders), GW's customer service, as a company, is unparallelled. Call that hotline, send an e-mail, you will get a response and it will be above and beyond no questions asked 110% A++
I bought a whirlwind and the launcher sprue was missing the large radar dish. GW sent me a whole launcher sprue, effectively giving me a free whirlwind (since I could instantly upgrade any rhino/razorback)
My brother bought some 'zerks who were missing the backpack sprue. They sent him a whole sprue of free berserkers and some backpacks to boot.
Some of you may remember the epically fucked up Crusader kit I had the misfortune of assembling before the all plastic kits came out. The pewter was all horribly miscast and covered in super-thick flash, the hull pieces were warped, literally bent and twisted, etc. I was able to assemble it, but the whole thing was a train wreck and a nightmare to assemble. I called GW, they apologized and asked me to put it all in an e-mail to customer service so it could be documented and maybe prompt them to inspect/recall certain batches.
I did so. A couple days later I got an e-mail from the head of US customer support thanking me, apologizing, and telling me he personally pulled a kit off the shelf, opened it, inspected it, then put it in the mail for me, just for my trouble.
A free crusader kit just because the one I had and was actually able to (barely) assemble was such a piece of shit, despite coming together in the end. Granted, I was terrified of the thought of drilling and pinning all that fucking pewter again, but years lter I traded it to a friend for a bunch of killa kans and more boyz, so I'm happy ;-)
Oh, and more recently (by which I still mean a couple years ago) I went into my local GWS looking for a chimera to turn into my infamous 'Chimerork' trukk conversion. They didn't have one, so I asked if the Basilisk kit included all the parts needed for a chimera, but with just extra gun gubbins included. They assured me that yes indeed it had the whole chimera package but with the gun as well. So I laid down the extra money figuring, hey, more bitz, right?
Of course, I was wrong. tHere's an extra sprue that the chimera is meant to come with that the bassie does not. I phoned GW customer service to report my general dissatisfaction with the ignorant inpstore help. Not really expecting anything other than to make some redshirt's day worse when they got the e-mail from corporate about customer complaints.
Instead, they mailed me a free chimera.
I didn't ask for one. In fact, I'd have been thrilled just to get the extra sprue, but instead I got a whole free chimera, sent to me within days, for free.
I still have most of the bassie sitting in a box, sans cannon, waiting for me to come up with something to do with it.
GW customer service is amazing. Always has been.