A missing property release does not transfer or erase your copyright. In general, the photographer owns the copyright simply by creating the photo, and that copyright controls how others may copy or use it.

A property release is a separate issue. A release is about permission to use a depiction of a property for certain purposes; it is not the same thing as copyright ownership. So even if you did not have a signed release, that does not automatically give the property owner the right to take your photo and use it on their website.

Your verbal permission to shoot there may also matter, and verbal agreements can sometimes be binding, but that is a legal-contract question with important details and local law involved.

Because this is a real legal dispute, the safest next step is to consult a qualified attorney, especially one familiar with copyright and contracts in California.