[CA] Current tenant won't move-out without a lease contract

[Ashley Ju]

Hello,

I rented my current primary home and signed a new lease contract for 1 year because of work relocation.Moving day is next week, but I was told today that the current tenant didn't move out after the lease expiration date. They were supposed to be vacant as of 3/7/2021.

Here is the situation.
The Current tenant's contract is only under the husband's name and they are recently divorced. Husband left the property before 3/7, and the wife is still at the property. She told the owner agent that she won't pay the rent and stay as long as possible. I think she messes up because a contract is not under her name.

Here is my financial loss if I don't move-in because her.

1. I bought a used refrigerator and it's scheduled delivery next week. ($1975 non-refundable)

2. I will spend $160 per month because there is the same size unit in the complex which is $160 more expensive. (1 year $1920)

3. Internet 1 year contract termination penalty $120

Any advice on California law?

1. Can I move-in as on the contract and call the police for trespassing?
She doesn't have a lease contract, but I do have one.

2. Can I bring financial loss to a small claim lawsuit if I can't move-in because of her? What are the chances of winning to get $4,015+legal fee+filing fee?

I'm so stressed out because I already packed everything. Your advice will be greatly appreciated.