My experience was very similar to Merve's. For reasons that did not depend on me (lack of roaming/wifi connection during my trip), I could not alert the host on my time of arrival. When I arrived at the apartment, I had to wait in the building's hall for 40 min, despite several attempts to contact the host via Whatsapp, in vain. AI thought that he was trying to get someone to the apartment to meet me or hand me over the keys.
After 40 min he told that the keys were in the letter box. When I dared to ask why I had to wait for 40 min, when he could have easily passed me this info the day before, he lost control: he started yelling at me over the phone, told me "not to mind his bollocks", and to throw the keys back into the letter box and go look for another place.
Unwilling to escalate the whole thing, I just asked him to tell me where I could find a clean towel, to which he asked me "What for?". After one hour he sent me a message on Whatsapp reading "Everything ok, Alessandro. Anything I can do for you?", as if nothing had happened.
I leave it to you to judge his behavior.