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

So here's the deal. I was in a month to month lease with the property owner, signed in April 2015. In June 2015 the property owner hired a management company and they demanded that I sign a new lease. I signed the new lease June 2015. On October 2015 they terminated my lease in writing. Which I was fine with.

Upon moving out I gave them my new address and contact information.

My questions is since moving out the property management company has been fired by the owner and the property owner has been sending letters to my work. No receipts, invoices or appraisals have been received from the property management company. My issue is I had a lease with the property management not the owner so do I respond or not. The owner is demanding an additional $2000 for "damages" and another $850 for carpet due to a pet I never owned. What do I do. I'm a single mom and her demands and sending letters appear to me to be harrassment. And since my lease wasn't with her how can she demand any monies from me.