"Have you tried to register the same address several times?"
I did not, because changing address doesn't work out of the box - each time I changed address, I asked support to confirm it manually. and it was done 3 times as I explained above.
Last time I was speaking with guy over the phone, he told me he cannot send verification code about this listing, because it is a duplicate.
I have only two properties, with different IDs, different addresses and different photos. They are not duplicates. That's all what I see. If they have some problem with non-unique address in database, that's a programming error . There's also no other bookable properties at the same address, when I search using the map (as a client - from booking web site) .
I have wifi in both of my apartments. Internet is unlimited, I pay fixed price per month (most providers in my area are cheap, so it's not a big deal for me) .
In one apartment I also have cable TV (in one package with internet access)
I printed information list for guests, for every property i'm managing
There is: WiFi network name and password, addresses of nearest grocery stores, parkings,
telephones to order taxi/airport transfer, and some other useful local info.