On Thursday, UnitedHealth Group accused a notorious ransomware gang of hacking health care payment systems across the country . As a result, hospitals, pharmacies and other health care providers have either been unable to access the popular payment platform, or purposefully shut off connections to its network to prevent the hackers from gaining further access . UnitedHealth says that as of Monday it estimated that more than 90% of 70,000 pharmacies in the U.S. have had to change how they process electronic claims .