Sorry you had such an awful host @Emma1862 but under its terms that you booked under airbnb only needs to refund you, give you 10% extra and help with finding alternatives. All of which they have done.
How long before your trip did the host stop communicating with you and at what point did Airbnb contact them? What were their recent reviews like?
Unless they agreed to pick up an additional £1000 tab for a hotel before you booked (did you? ) - much as might want them to, they have no liability to do so.
They might give you a bit extra as a credit.