This is the right strategy against ransomware. Backup, backup and backup. At the first sign of any ransomware attack it is important to isolate affected machines immediately and contact a cybersecurity professional to mitigate and prevent further infection.
The US city of New Bedford, Massachusetts, rejected a ransom demand of $5.3 million and came back with a counter-offer of $400,000, while restoring encrypted data from backup.
Source: US City Rejects $5.3 Million Ransom Demand and Restores Encrypted Files from Backup (SecAlerts)