Providing you bought Pro from the official site Lime Wire » Official Website & Free Download « then you haven't been scammed.

Pro connects you to 5 ultrapeers compared to basic's 3, so the potential for better search results is there. You'll probably notice the difference in search results more if you're searching for rarer files. Pro lets you connect to a couple more hosts for download (10 hosts, or 14 if you have a T3 connection) so the potential is there for higher download speeds. Pro gives you access to email support for 6 months, which basic doesn't offer.

And, of course, the Pro payment helps towards the future development of LW.