Legal Question in Civil Litigation in California

Nothing, and I don't understand how you can claim that you had to foot the bill for the County APS to check on the welfare of an elder.

Obstruction of Justice is a criminal charge it would not apply here. Filing a false report can be prosecuted but I doubt that you would get a a law enforcement agency and a District Attorney's Office to get in the middle of a neighbor dispute.

The courts probably dont want to deal with "inconvenience" but you may have a potential civil case for malicious prosecution. However you have an uphill battle because you are dealing with proving that the report was completely false and you have to deal with the California SLAPP Statute. If filed you can expect a series of complex First Amendment arguments that someone with SLAPP experience can deal with the prevent the case from being dismissed.

I think you may have a case for defamation and/or harassment. However, you must prove by clear and convincing evidence that your neighbor is the one who called. Otherwise, the call is confidential and you won't be able to get that information from agency. "Knowingly" filing a false report is against the law.

Reporting suspected abuse is a moral obligation of everyone in society, if done in good faith. The neighbor's report is immune from a lawsuit, as a court proceeding document. If the neighbor went around telling others you were abusing an elder, then it would be grounds for slander unless it were true. IF there was absolutely no inappropriate conduct or condition found in your home, there would have been no 'charges or costs' as I understand the law.