Complaint Review: johnson & Pham product partners

I just got a letter in the mail saying that i am being sued for trademark and copyright infringement for P90X products from a law firm in ca called johnson and pham.
They claim that I violated federal and state laws by trying to sell my copy of p90 on ebay!

they want me to pay them fines $893. What I am supposed to do? I looked at their website and lawyers and it all seems legit. Also, they have cited to other cases they have sued on.

"In the event a lawsuit is filed against you, and you fail to respond as required by the Federal Rules of Civil Procedure, we will seek a default judgment against you based upon your infringing conduct. This firm has successfully obtained multiple judgments against individuals in excess of $150,000.00 relating to the sale of counterfeit Product Partners merchandise. See Product Partners, LLC v. Aaron Watts, CV09-05958 GAF (CTx), and Product Partners, LLC v. Sondra Howard
, CV09-05965 AHM (PJWx)."

AND they attached this paper with 15 lawsuits they have filed for the same thing.

What should I do? Can I ignore them? Should i pay them? I don't have any money to get sued or to get a lawyer. The judgments they got were over like 100K!!!!

HELP!

-Freeman M