I'm not happy writing this but this was a really poor stay. First, check in was chaotic, no one told us what button to press on front building door, and we was for 40 minutes in front of the building trying to reach Frank. I admit it was our mistake that we didn't write down Lisa's number. When we reach Frank he explain and we got in! :) Apartment was clean, Lisa was helpful but Wifi wasn't working. She said that they can pay for hotspot but just for one of us, but there was four of us, and we paid for that service. She said to wait until the night to see if wifi would work and we texted her and Frank that problem wasn't fixed. Lisa asked for more time, and that was okay to, but she didn't contact us anymore. Not many coffee shop in Berlin have Wifi, and it was big problem for us because that was the only way to contact our family. My phone bill is 3 times more than usual because of calling and texing to Frank and Lisa. Internet problem wasn't fixed. When we arrived in Belgrade a message from Lisa was delivered to my phone about hotspot (mentioned above). It's strange how that message wasn't delivered to my phone in Berlin, and message about check out was, but however, even if did came when we was in Berlin we paid for Wifi, not for hotspot only for one person.
IMPORTANT: Apartment was really nice, it was in pretty good location, Berlin was amazing, but lack of communication made our stay not as great as we hoped for.
We hope that Frank would fix that problem and we are sure that your stay in his home would be great!