It was very definitely not from the official LW site. They do not charge so much. Unfortunately, if you backtrack through your web browser history you will find it was not the official LW website. Nowhere on their site does it say they charge US $49.90 Lime Wire » Download LimeWire

My advice is to cancel transactions asap via your credit card company & explain it was a fraud.

LimeWire if Free by the way. Only if you get Pro which is almost the same do you need to pay anything. And should only consider pro if been using LW basic for many many months.