Legal Question in Real Estate Law in California

First, there is way too little information given to advise you accurately. An attorney would want to know, for starters, (A) what kind of a relationship do you have with the "seller"; and (B) how much of this deal is in writing? For example, if you have a good relationship with the seller, the two of you should sit down together with an attorney or a real-estate broker and work out a solution, including proper documentation followed by recordation, payment of property taxes if unpaid, etc. If on the other hand the seller has disappeared or is uncooperative, you'll probably need to have a lawyer look into filing an appropriate legal action in court, which could be, maybe, a "quiet title" action to have the court recognize you as the owner, or possibly an action for fraud, or both. In short, you are going to need competent and local legal assistance, and I'd recommend a real-estate specialist attorney.