hello, Sir Eyn. I'm a Japanese player of this game, and I know reasons for the treatment you've been given.
I guess you don't understand circumstances of the incidence, so I explain it.
Most part of recent JPN player complete duty of dungeon within about 20 to 25 minutes, on average, if no wipe. (except some long dungeon.)
However, for this records, it demands some peculiar conditions.

First, even if one is on a healer role, he/she must join assault, using skill for attack.(some in this thread says "you had to do so".)
Second, allmost all of JPN player can't understand English, or ohter foreign languages, and is likely to dislike use auto-translate function, thus they often kick foreign players or break up, at the moment of revealing to themselves that their party includes non-JPN players.(Other says "you had to try to communicate them in JPN", not in ENG.)