Did you notify Airbnb? They do a service by trying to find you other accommodation, with working wifi if that is what you insist on. Airbnb could have found you somewhere else to stay (and still can if you are still at that place). In other words, the listing was(is) not suitable for you. It is now hard to determine the "value" of no internet service so it would be difficult to estimate any refund. Have you asked the host? It happened to me once, as a host, and I offered free breakfast at a local internet cafe but there was no obligation to do this.