Unfortunately, you are too late to register a lien on title as you had to do so within 45 days of substantially completing the work.
As well, the amount you are owed is high and you cannot sue in Small Claims Court but have to sue in superior court.
That means that it is best to retain a lawyer to sue for you as the law is complex.
As a first start a lawyer should send a demand letter to the contractor giving the contractor a deadline for paying you in full and threatening a lawsuit.
If that doesn't work and it likely will if the contractor can afford to pay you, you would then start a lawsuit.
Once you get a judgment you can enforce it by seizing assets, garnishing payments being made to the contractor etc.
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