Please, I need urgent assistance

In the beginning of the month, i found this program:

http://www.filterforge.com/

Filter Forge works with an online library of filters that are made by other people. They upload the filters they make to the online library in exchange for reward points, that when reached a certain number, will give them a free copy of the program. When they make the upload of a filter, they agree with the terms of it, which includes giving permission for users who download their filters, to use the result images personally and/or commercially. It would only be considered illegal to sell the filters themselves as my own. But the images i render with their filters, legally belong to me.

But now, some of the filter makers found that a lot of people were selling rendered images using their filters, and they started to be offended by this. I direct your attention to the following topic at Filter Forge Forum, where this is debated ad nauseum:

http://www.filterforge.com/forum/rea...21 #nav_start

In this topic you´ll find that most of the filter makers know and acknowledge that they don´t have a right to accuse people of anything,nor to feel offended or used, since they licensed it to Filter Forge to sub-license it so that others can use it any way they see fit. This brought up a lot of discussion and forced Filter Forge to change the EULA. But as I understand it, my renders were done with filters that are grandfathered under the earlier licensing.

I was now contacted by one of the filter makers which made a filter that I used to render images for profit. He is BLACKMAILING me, saying that I either pay him for using his filter, or he and others will start a "campaign" against me, denigrating my image as a vendor and as a person.

I sell my products on a US online store, I live in a EU country, and the blackmailer in another EU country. What can I do about this all situation?

Please, any help will be greatly appreciated!

[annjd]

If someone publicly says or writes anything factually untrue and it damages you, you indeed can sue for slander, libel, defamation, interference with business relations etc. -- or at least threaten to do so and give a warning.

They could also be sued for trying to interfere with your business in an improper way.