Is de-ranking currently possible on PS3?

Everyone keeps saying how hacking is impossible since the patch, but I've seen loads. Just yesterday we went into Ground War and it had been hacked into a massive Free-for-All.

Anyway, I was directed here to ask you guys about my issue. Back during the hacking frenzy earlier this year, I reached 8th prestige legit before landing in a challenge lobby (twice!) which boosted me straight up to 9th and then 10th prestige -- competing all my challenges in the process.

I'm just wondering whether or not it would be possible for somebody to derank me back down to 9th prestige and reset all my challenges. Please help!

Wrong..section...And i dont think so...