You should have never taken possession without verifying that the work was done. They should have provided you with a copy of the invoice for the carpet cleaning. Live and learn.
As far as filing a complaint, you can do it with the DRE in California, but in this case, the party you have a complaint against is a tenant and an agent. Unfortunately, you might not really have a complaint against them as an agent. Tenant's are not party to the contract, and the agent should not have filled out the disclosure notice.
You really should have had added the provision to the contract, asked for proof of the work, and then done a final walkthrough and acceptance before signing the closing documents.