@Priscilla150
It is a "long term stay", so when she cancels she will not be refunded the next, not used, 30 nights
It is up to you if you want to refund her some of that (by using the resolution centre)
I do reguraly "long term stays". I useally use the shorten option ("change reservation") if there is a problem (My guests are moslty students, for them is losing 30 nights a lot of money). The advantage of shortening is (if it is done by host) that the host can change manually the calculated price in the change form to one he/she thinks is a fair deal. After acceptance by the guest the remaining dates are available again and also the guest will receive part of the Airbnb Guest Service Costs back.
best regards,
Emiel