Delta lashes out at Crowdstrike

(CNN)– Delta is firing back at Crowdstrike over the tech outage that led to a massive service meltdown and stranded thousands of passengers.

A lawyer for the airline said Crowdstrike’s apology is vastly inadequate.

In a letter sent to  Crowdstrike’s attorneys on Thursday, Delta’s lawyer said the tech company was grossly negligent and solely responsible for the outage.

Delta cancelled seven thousand flights between July 19, and July 24.

Crowdstrike and Microsoft have claimed Delta took longer to recover than its competitors because the airline refused their help and did not modernize its I.T. systems.