My question involves landlord-tenant law in the State of: CA
I gave notice to my landlord of my intention to end my lease early and the landlord agreed to allow it. I paid out 30 days of rent from the date of notification which was April 7th. I requested a move out inspection on April 19th and the landlord agreed as I was moving cross-country. The move out inspection noted areas that needed to be addressed and I fulfilled them to the best of my ability understanding that some items, a broken sink, would need to be replaced and come out of my security deposit.
Per my lease agreement, I agreed to cover the cost of advertising, cleaning, lost rent, and tenant placement costs for terminating the lease early. I vacated the property on April 20th and surrendered the keys to the landlord. I discovered that a new tenant moved into the property on April 22nd.
The Landlord has stated that she is keeping the rent for the whole 30 days as a negotiation fee. Is this allowed? She has already cashed the check for the 30 days.

