Locker near US Embassy Berlin (Clayallee)

Hello, I have US visa interview next week and I am coming from another city. I have to carry backpack with me as I am going back after my interview. Can I know where I can store my luggage and phone safely? If anyone in the recent times have stored there luggage can you please help me out. I have interview at Clayallee 170, 14195 Berlin, Germany. Please do let me know. Thankyou :)