Spamhaus and Spamcop..blocks IP address !!!

SPAMHAUS and SPAMCOP, these spam engines created a havoc recently by blocking the IP address and they wish to remain stubborn about it, which has resulted and created enormous tremor in our branches worlwide. Mails are happily bouncing back. Our enterprise uses and hosts Kerio Mail Server. Yes, The reverse DNS is configured well.

Our ISP (real-ip-provider)is clueless and have futher commented they have no hand in this issue.

Hey Guys, please please advise or guide me to avoid this situation.

Thanks in Advance.