This happened to me a few days ago. And the idiot didn't even reply as we constantly asked if he was there. Fortunately, the majority of the party (both tanks, both healers, and 1 attacker) were from our FC or a friend. We all talked it over and decided to leave, even the other two attackers despite looking forward to a queue again. We all agreed that carrying that lazy attacker was far more annoying than having to wait again.

It was much easier for me to leave because I was in the "instant-in" group, but y'know. I don't like carrying slackers. They never even said "brb," or "afk 15m," they just stood there like a statue for 12 minutes. I won't tolerate it.