Thanks for your fast response, not usual on rbl's.
[at]davidT: Yes you're right, our ISP seems having recieved only an warning and just don't know how to interpretet it right. Currently the mentioned domain in the sharewarenotice is the www.in-mediakg.de. There is no actual complaint, so everthing's fine there for the moment.
[at]agsteele: Well the shareware notice with the url in there, is a quite good thing to get new customers under normal circumstances, if we don't think about abusement. But it's quite clear that spamers a) don't buy software and normally use other software, because in the unregistred version, he is only able to send out 50 mails.
Due to this issue, we have not build in there a 30 days time period or something like this, to prevent spamers to use our program, also a lot of notices in program inform the user what he is allowed to, and what not.
I've talked to our ISP and got things right , to notice the difference between those two reporting forms. But as I know our ISP (it's the largest in germany) I'm sure that information isn't spread to everyone it concerns or totally different people work there to the next incident. So I guess this will happen again. Really problem for us, because ISP gave us 48 hours to say something to the incident, otherwise our account would be suspended. So maybe a white-lisitng via spamcop would be great, if possible.