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I'm sorry to hear about your situation. Yes, it's certainly legal for a client to hire an attorney to remove a construction lien if they're successful in arguing that the lien was wrongful to begin with.
If the Mechanic's Lien is not timely recorded or a lawsuit to enforce it is not timely filed the owner may petition the court under Civil Code
Section 8480. Before filing the petition, however, the owner must first serve the contractor with a notice providing them 10 days within which to remove the Mechanic's Lien voluntarily. This notice must comply with the technical requirements of Civil Code Section 8100 - 8116 so it is a good idea to consult with a lawyer before giving the 10 day notice.
Once the 10 days have passed, if the contractor has still not removed the lien a Petition can be filed and a hearing date will be set. The Petition must be served on the contractor at least 15 days prior to the hearing (Civil Code Section 8486). If the owner has complied with all of the requirements of the Civil Code and meets the burden of proving that the Mechanic's Lien is defective, the lien will be ordered removed and the owner will be entitled to their costs and reasonable attorney fees.
Note that just because they get an attorney and file to have the lien removed doesn't mean that they'll be successful. They have the burden of establishing that the requirements to obtain a lien have not been met, or that it's too late to sue to enforce the lien. If they can't prove these things, then the lien will remain.
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