Key number? LW does not use key numbers at their site. Do you mean the transaction number or something.

I have a suspicion you accidentally went to a scam site & purchased LW from there. Check your browser history to see where you actually paid for it.

When you purchase LW Pro from the "Official" site, you are then sent an email with a link to your personal pro download page.
Also, you should see Lime Wire LLC on your payment record / credit card statement & also any email sent to you.