As far as I know, there is no hack/exploit. It's the scoring system which is publicly available, but many players ignore it. In a recent Brawl, a member of my BH was hit by multiple enemies. He defended each time and he lost some troops.
However, they were not very bright and they sent loads of Marauders, as you would in normal PvPs. He defended with Fleet and Armada. I don't know his points, but my own Marauder has roughly 100 off, while the average of Fleet and Armada def is 1600. Add to that haven def bonus which, on well built havens, doubles this. So, about 3k def points for a single unit.
If these hits happened to me, I could expect to kill 60 Marauders for one Fleet and one Armada unit I'd lose. That's 1200 PvP points (in Brawls, each dead Marauder is worth 20). At the same time, I lose one Fleet and one Armada, which is 60 + 80 = 140.
I know that this is roughly factor 10 and not 200 that you have, but keep in mind that these are numbers from my own well built haven. A Marauder without bonuses has only 40 off and the defending haven can have significantly higher def bonuses than me (items that I don't have active, more improvements, higher prestige level,...). The factor could probably get close to 15.
Also, this score might not be an act of incompetent players, but spies cooperating with your opponents. In that case, they might be raiding with Bonnies instead of Marauders. Each unupgraded Bonnie has only 10 off (not 100 like my Marauders), and that brings us around the factor 200 above.
Could there be an exploit? I guess there could be. But, as you can see, there is another explanation for the above report. Without more info on the alleged exploit, I'm not sure how to chase that. If you want, you can try to report it here as a violation of rules and ask Plarium to investigate. On the forum, I can only offer the explanation that I just wrote.