From my experience as a customer service representative, I can say that the right response to the situation (with dignity and respect for the customers feelings) would be:
"I apologize for the inconvenience you are suffering through. I understand that there are a lot of problems/bugs going on with the game. We are currently trying to work through these problems to better serve our customers. I would like to thank you for pointing this out to us, we'll be on it as soon as possible."
At my job we have a 4 step program called L.A.S.T.
Listen
Apologize
Satisfy
Thank
Every time someone calls on the phone with a complaint we have to use this.Haha. Sorry I talk on the phone to people for a job right now, and I finally got used to being screamed at and treated like crap. This is usually the best way to calm a customer down, I find, but you have to watch your tone, because even if you don't mean for it to sound rude or pretentious, it can.