If you bought Pro there's no refund. Thats because they give a free version to try as long as you like, so if you decide to buy Pro you know what your getting.
If you didn't get it from the offical site (
http://www.limewire.com/english/content/download.shtml)
Then you probably got scammed. Read through the posts above yours and also this link:
Membership?. Good luck.