@Emily191, do you have those conversations by phone or on the airbnb message thread, in writing?
What you should do is:
don't take any more phone calls from him.
Write him by airbnb message thread a summary of your experience:
"Your calls / acusation are disturbing, therefore I'd like to summarize how we lived the experience:
We did not meet you at arrival.
The place was not completely what we expected, especially concerning the habit to leave the house door unlocked, but pleasant enough.
When you visited, you offered us drugs, which we declined.
We did not steal anything and no reclamation was brought to our attention whilst we were there.
We ask you not to contact us any more and not to make any more threats."
After that, either he stops or he will send you a well felt letter of insults in Writing, by airbnb, which would be best or by sms. (Had that with a guest).
After that letter of insults, you flag him in the profile, with the little flag icon, in the conversation, if he wrote on airbnb. You can take screenshots from sms messagesand send them to airbnb, when you are in mail contact.
You write to the person again, that at the next contact, you will go to the police with all the messages.
Airbnb can block a contact between you, but they have no influence over other channels like the phone.
If a member writes insults, the profile is usually blocked or removed, especially if there are threats.
If there were different guests at the same time, it's possible that things disappeared and he blames it at one of them or all of them. A calm, stern approach should help.
Good luck