Отменить можно. Вы получите стоимость билетов минус комиссия
FLIGHT CANCELLATION FEE

The flight cancellation fee is dependent on days left until the departure and is charged per passenger per flight.

More than 14 days to go, cancellation fee: €30.00 – €120.00 per passenger per flight
Within 14 days to go, seat protection fee: €50.00 – €150.00 per passenger per flight
https://www.wizzair.com/en-gb/help-centre/booking-modification/cancel-flight/cancel-your-flight