dude, i live in the USA, but i think around the world, you can get them in deep trouble. contact the companys CEO, if possible. if not, get as high as possible in their company. Demand them to remove the script NOW, and request them to contact all the people that have purchased your software through them, and admit to everything. require that they CarbonCopy a copy of the e-mail to you, and ensure that it has all of the offendings company's clients e-mails on it.
Could you link us your product, and their product.
WARNING: you cannot do any of the above if you have not Copyrighted your code.
dude, if you do this correctly, then u will have everything all happy, and their company will be almost useless...
--HackMaster
www.hmstudios.net