You can demand, in writing, they stop contacting you. Note, if you do, that may be enough to prompt the to sue.

Yes, before you pay you would be entitled to see proof of amount due, including estimates and bill/statement.

You need to get an attorney to review the contract, documents and facts. Use the AVVO search feature at the top of this page.

It looks like a scam. Check your credit reports and check court records online.

Probably not. In Nevada only consent of one of the persons is required.

You probably will have very limited recovery, if anything.

Put the agreement in writing for the seller to sign. Also have title signed and have it held by a third-party.

No you would not be able to. But, a question comes up, why would an attorney fee be $2500 for a ticket.

Yes you have a lawsuit which may include what they were paid and what additional damages caused by their delay.

More information is needed. Please repost your question with more details (but not with personal information).