@Višnja4 this is not the airbnb customer services, it is a discussion forum for hosts and guests, but we are happy to offer advice to fellow hosts.
If your guests want to cancel, they need to log on to airbnb, find their reservation and cancel it from their end. It is not your responsibility to cancel their reservation. They need to cancel, and doing so they will be refunded according to your cancellation policy. If they are not refunded in full, they can claim the rest on their travel insurance.
They may be refunded in full on the extenuating circumstances clause from airbnb, but this is for the guests to sort out with airbnb by providing the necessary documentation. As we have a worldwide travel warning in place, providing documentation should not be an issue. Do not cancel on the guest's behalf, you will be penalized. Write to your guests on the airbnb platform and ask them to cancel from their end.