Crooked landlord (Munich)

Hi,

I'd appreciate any advice on this.
I moved out of my old apartment in April, and paid rent through May.

The landlord is just now billing me for damages and repairs, 8 months after I moved out. He's also saying that he had to buy a new washing machine (receipt is dated July) and is billing me for it. The old one was working perfectly fine when we left, and he has provided no evidence that it wasn't working when I left the apartment or that any repairs were attempted before purchasing the new one.

I never joined the Mieterverein, and I'm wondering if anyone has dealt with a similar situation or if someone knows how to contest such claims.

Thank you for any help or advice.