What would be your interest??????

Does not make sense. Insist on accounting and full explanation

Recover your vehicle by paying if possible- sign nothing - then speak to insurance company and lawyer

No You need a court order if he is an owner

Just resign from the business And the partnership

Short answer: no.

Did you file a proof of service? Did you friend write something to the court

Mustard document was a precondition to you providing services. The answer is no.

You should definitely have a process server serves X with the papers

I am not certain from what you write exactly how it came about and it will matter. Could you please try your question again