Legal Question in Real Estate Law in California

First, is it a California judgment or out-of-state?

Next, why is the judgment erroneous? In other words, and for example, do you think a court clerk inserted the wrong name? This is one kind of error and is addressed under one set of procedures; see generally Code of Civil Procedure section 473 for how to correct erroneous or mistaken or otherwise procedurally-improper judgments.

Or, do you think the wrong party won, i.e. that the judgment should be reversed upon appeal to a higher court? Appeal is a specialized and tough process with tight deadlines for filing a Notice of Appeal and for following up thereon.

Or, did you simply hang out on the sidelines and not become a party to the case, when you should have been before the court, asserting your rights? Probably not, but if this is the case, you may have lost your rights by not intervening in the case. Were you ever a named party in the case?

You might have to sue the property management company, but possibly your proper means of attack is under CCP 473, or by appeal. A lawyer would need much more complete information, starting with identity of the court that issued the judgment, in order to advise you of whether, where and how to proceed.