That is tragic that it has been stolen, and hope the Police are dealing with this.
However, the buyer has bought this, and it is not up to them to cancel.
Have they paid, have you explained what has happened, if they accept this , send them a cancellation request, your seller fees are then refunded. If they have not paid and you are cancelling they have to accept this cancellation order for you to retrieve those seller fees.
Listing fees for a vehicle / trailer will still have to be paid, that is not refundable.
