Despicable airline service

Utterly useless, I won't fly with Mango again. I booked return flights to Zanzibar in January this year, for July. In May I got a message that my flights were cancelled, and that they don't fly on those days. So I changed the flight dates.

Three weeks ago I booked accommodation in Zanzibar, believing that everything is still on track. Today I got another message saying that our flights are cancelled once again, a week before our trip.

Who is going to refund me for the cancellation fee of the accommodation??