No later than 21 calendar days after a tenant's vacancy, but no earlier than either (i) the time the landlord or tenant provides a notice to terminate under CC § 1946 or CCP § 1161, or (ii) 60 calendar days prior to the expiration of a fixed-term lease, the landlord must do both of the following (CC § 1950.5(g)):
• Itemized statement: Provide the tenant, by personal delivery or postage prepaid first-class mail, with a copy of an itemized statement indicating the basis for and amount of any security received and the disposition of that security (i.e., showing what amounts are being retained and for what reasons); and
• Refund: Return to the tenant “any remaining portion of the security” (i.e., amounts that cannot lawfully be retained). [CC § 1950.5(g)(1)]
It is the landlord's burden to show the reasonableness of security amounts retained. [CC § 1950.5(l)]
If, within the statutory 21–calendar-day period, the landlord fails to provide the tenant with the requisite written accounting of the portion of the security deposit to be retained, the right to retain all or any part of the security (CC § 1950.5 (e)) has not been perfected and the landlord must return the entire deposit to the tenant. In other words, the landlord forfeits the benefit of the § 1950.5(g) “summary deduct-and-retain” procedure. [Granberry v. Islay Investments (1995) 9 C4th 738, 745, 38 CR2d 650, 653]
Sorry, but in your case it appears you are already past the 21 day period, which began when your tenant vacated. Therefore, you may have to return the entire amount of yoru tenant's deposit under the authorities above. See a local landlord-tenant attorney regarding the specific facts of your situation.
This response is intended to provide general legal information rather than specific legal advice, and does not create an attorney-client relationship.