If your postal/shipping company is closed, the first thing you should do is message the buyer directly to inform them of possible shipping delays and, if needed, try to work out a delayed shipping arrangement. You can also contact the shipping carrier to see if they have any other nearby open locations.
Reverb will not automatically cancel delayed/unshipped orders if we see that an agreement has been made via on-site messaging. If the buyer is unwilling to wait, please issue a refund and relist the item.
More common questions on COVID-19