You are locked down, nothing works - Who are you going to call?
When your business stops, you have to wonder if this is a physical or software issue. Hopefully, it's something simple like an electrical outage, or your local construction company has dug up the telephone lines. Either way, you pull out paper and keep working the best you can. If software-related, you have to fix it, and sometimes the fix is intentionally blocked.
What are you going to do next? Do you have air-gapped backups? Do the terrible actors have your database? You need to know these things before it happens. Disaster Recovery can never be used or enacted quickly.
You should anticipate getting attacked again if you do nothing. Deterring a cyber security threat and its repetition require minimal effort. The bad actor is looking for quick cash and does not want to work hard for it. When recovering from a disaster, hire someone to document the lessons learned and simulate an attack.