The same thing you would do if the hard drive just died. Paying the ransom does not ensure you will get the key.
Believe it or not, most of these criminal outfits will provide a decryption key when the ransom is paid. If it became public knowledge that they weren’t providing the keys, at some point their income stream would stop. End users are not complete idiots. If it’s publicly known a ransom won’t produce results, why pay?
It’s also important to note that more than half of ransomware victims are reinfected within a year of the initial hit. You HAVE to educate your users. They are the first line of defense and often the reason for the infection to begin with.