70.84.105.196 is being blacklisted:
http://www.spamhaus.org/sbl/sbl.lasso?query=SBL34259

Can you please get your system off of this blacklist? I cannot email some people as I get messages bounced back from them with a "550 Denied by policy: Sender is listed on DNS-based RBL" error. Their ban of your entire server outright is outrageous to say the least since users like myself are directly affected by their attepts to block one spammer. Regardless of that, make sure the spammer is gone for good and please contact the above ASAP to get this fixed.

Get used to it. That's my server, too, and it's a problem that's beyond chronic. It's endemic, at least for some of my users and/or their ISPs who are slow to re-allow access to sites which have been blacklisted.

They told me to get a unique IP address. Then when I did, they told me that mail goes out via the server's main IP address anyway - so there's NOTHING you can do but move...preferably to your own dedicated host or VPN.

If anyone has a better solution, please suggest it to us!!

you can move your account to another hostony server, too, (or get a VDS of course)

Also, wehen you get a VDS/VPS, be carefull than the IP numbers assigned to you by your provider, don't was used by a spammer in the past