Hello,
We believe that your IP address is blacklisted on some spam blacklister(correct me if I am wrong) and you would like to remove the IP address from blacklist. We have couple of questions, before providing a suggestions.
1. What mailserver does the server is using?(exim, postfix or qmail)
2. How many mails are there in the mailqueue?
3. Does the blacklister reporting any specific time that they received the spam mails?
There may be few questions which may arise depends on the answer. We are available between 9:00 AM IST to 9:00 PM IST. You can reach us on skype:support_38402 as well.