Where did you subscribe to LW...can you give me a link?
It sounds like you might've been scammed, LW basic is free & LW Pro costs $18.88 USD for 6 months of updates & email support...how much did you pay? The only official (safe) site for downloading either version is www.limewire.com

There's no 'pay per download' & the only time you are asked for your credit card details is if you decide to buy Pro & pay by CC.

Have a look at the 2 threads below, the first has info about 'membership' & scam sites, the second has info about getting a refund from scammers if you need to chase them up.

http://www.gnutellaforums.com/open-discussion-topics/28751-membership-warning-beware-download-p2p-clients-only-thru-official-sites.html
http://www.gnutellaforums.com/open-discussion-topics/44499-get-your-back-music-members.html

If you find you have been scammed, contact your CC company & report this!! Ask them to cancel the transaction.
If I were you, I'd also get rid of the scam version of LW (who knows, it could have some nasties with it) & get the free version from the official site above