Legal Question in Construction Law in California

Re: contract (lack of)

You said 'the judge favored the contractor'. That sounds like the case is over and you owe the money under because of a judgment against you. Your questions are therefore not relevant to your present issues. If a judgment was already granted against you, you can appeal if you are still timely. It was likely small claims court, if so and if you appeal in time, you get a new trial. Raise your issues there; you can have an attorney at that trial - use one.

Re: contract (lack of)

What state law $500 do you mean? The Commercial Code (section 2201) has a $500 limit for sales of goods by oral contract, but this isn't a sale of goods, it is performance of services. There is also a requirement in the Business and Professions Code that certain home improvement contracts must be in writing; whether this job came under that proviso isn't knowable from the facts given.

Further, the various "Statute of Frauds" enactments requiring written contracts in a variety of situations are among the most porous laws on the books. A good lawyer can find a loophole and get enforcement of some kind on more than 50% of the oral contracts that shoulda been in writing under the letter of the law. Often, this will be because there is some sufficient written memorandum of the contract to prove by writing that one was formed. Or, the court can ignore the oral contract completely and order payment in the form of monetary restitution to avoid an "unjust enrichment" of the beneficiary of services or goods on a quantum meruit or quasi-contract theory.

In addition to the lack of a written contract theory, you also seem to allege that, if there were an agreement of any kind, it was made by the Realtor, not you. The problem here is that this person is your agent for getting the house sold, and contracts made by an agent with apparent authority of the principal are as binding on the principal as though he made them himself.

I think you may have a stronger case against your Realtor than against the contractor. The Realtor owes you a bunch of duties, including a duty to follow your instructions and to keep you informed. Mind you, I don't know whether your have a good case for breach of those duties, but it could be the stronger of the two.