We've buy a Unity Pro license and my Computer Broke

We buy a license for Unity Pro with 2 seats, one of those was put it on a computer, 2 months later the SO fails and we lost the oportunity to take de key code back
What can we do?

What do you mean you’ve “lost the opportunity to take the key code back”?

I just had this happen last week after the hurricane. Here’s what I did: Sign into your account on unity3d.com, go to subscriptions, find your list of seats, and click the link to reset your activations. Then you should be able to activate the new computer.

Failing that, contact Unity’s billing support.