GPS from the confirmation email pointed to different address. When we reached the place there was actually apartment 3C, though we were trying to get in with no success. After some time I went through the communication with Daniel to find out the real address. Unfortunately this address was not in the most important messages about check in/out or about phone number to open the door, so it was not easy to find the address. Moreover the apartment is not that close to Atocha train station. Based on GPS location it was supposed to be less than 5 minutes walk. In reality it is about 10 minutes walk, so still fairly close.
Other than that apartment is clean and nicely decorated.