My question involves a security deposit in the State of: CA

We originally had a rental agreement with a property rental co. We had a signed contract/agreement with the rental co which we were with for 3 years.
The last year the owner of the rental home we were tenants at decided he disliked the way the prop management co did business and pulled all lof his rentals from their services... We never had a signed contract with the Owner of the house who was the new landlord.
Does the original contract/agreement still hold place? Or should he have had us sign a new agreement or contract etc? We were always on a month to month rental agreement with each party however we are currently suing our landlord for failure to refund the sec deposit.