My question involves landlord-tenant law in the State of: California

My friend had a work assignment in California and moved into an apartment that she found on Craigslist and never signed a lease, but did pay rent monthly at an agreed upon amount. She did pay a security deposit and the landlord told her that they would return it to her after she moved out and they did a walk through to see if there were any damages or cleaning required. She kept the place pretty spotless, it was already furnished so she didn't make any holes in the walls or anything and was only there for 7 months. When she was moving out, the landlord scheduled a walk through but never showed up. She would call and text them and there was always some sort of excuse. She left the area but comes back monthly for work assignments, and calls and text but they ignore her or hang up (if she calls from a blocked number). My question is, does she have any legal standing to get this money back? She wants to show up to their house and demand the money back, but I don't know if they're legally obligated to give her anything if there was no signed lease. Appreciate any help, thanks.