Don't feel bad, AOL is bad about whipping anyone else that they accuse of spamming, and do not do anything about their own spamming. I been to battle against AOL many times for their false accusations, and have been successful at getting them to remove the bans.
There has been an onslaught of false headers being sent out as spam origins lately. One thing the culprits don't understand is, it is almost impossible to mask the ip of the actual mail server it comes from or starts at. If you can prove that it does not originate from your server, and it only bears the name of the site, they have to lift the ban and go after the real persons involved.
One thing is, whether it is spam or not, AOL works on the precept that if someone complains, it is spam, regardless of whether or not they signed up for it. It sucks...
I hate spam to. however, if you want to fight them, you will need them to provide hard evidence, because, it is illegal for them to block you, without due notice and hard evidence..there are laws against this.