I'm with ya dude. When a crucial part of the unit you buy fails, it's hard to just suggest buying another from the same company. Let alone when it does and they don't even send an automated reply to say "we're on it". A fan failing on a cooler is un-acceptable.
I'm searching like a madman to find the P/N for that fan. I know I have it because it was an issue here as well. It's a total pile of shit fan that is about $5 shipped to get another. It's sleeved, it goes off balance, starts to rattle the whole monster cooler, and eventually the entire tower case has this oscillation ravers would love to dance to. It never died, but I wouldn't let it get that far...enough is enough.
If they don't reply back, keep trying. Give them three attempts at least and then we can step in and start getting down to brass tacks. I have an assumption that they'll ignore you since that's a reflection of my own dealings with CM, but I'll always suggest to others to give them a chance.
But for now, you should just accept that you need to buy a fan to get in there and not wait on them to deal with their product. Include this in one of your updates to them. They may eventually get to you, but they'll also RMA the entire unit and not just the fan. Best case scenario: you send it all in, you get it back with the same POS fan. $15 for a Noiseblocker fan and just write them guys off as "good Support providers".
Reviews are 3-day room mates dude. It's a snapshot that few follow up with. 6-months later we find they don't pay rent, leave their underwear on the couch, and just become a hassle to keep around. Nothing good to say about Coolermaster hear at least...