Sub-leasing a leased vehicle

I'm being taken to small claims court for being an unknown third party on a leased vehicle. Plaintiff claims I owe the amount of $3850.05 for end of lease costs (miles/damage). The plaintiff and I signed a contract stating he is the sole person on registration, and did not state anything about miles, or end of lease costs. I am counter-suing for the insurance he required me to pay, under which I was not covered. What are my rights? - Is this your question? Add additional information