Cybersecurity firm Crowdstrike sparked a global outage last month affecting a wide range of companies from Microsoft 365 apps not working to the National Health Service system going down in the U.K. One company affected, in particular, was Delta Air Lines, which canceled thousands of flights resulting in a loss of $500 million in five days. Crowdstrike’s response to Delta is akin to “oh well, we tried.”

Crowdstrike’s lawyers sent a letter to Delta’s team in response to legal threats over the massive outage that occurred on July 19. The cybersecurity firm says in the letter that it’s “highly disappointed by Delta’s suggestion that CrowdStrike acted inappropriately and strongly rejects any allegation that it was grossly negligent or committed willful misconduct.” The letter went on to say the company did everything it could and even threw some shade at Delta for taking so long to get its operations up and running again when its competitors restored their operations sooner. The company ominously wrote, should it pursue legal action, “Delta will have to explain to the public, its shareholders, and ultimately a jury why CrowdStrike took responsibility for its actions—swiftly, transparently, and constructively—while Delta did not.”

“We have expressed our regret and apologies to all of our customers for this incident and the disruption that resulted,” a Crowdstrike spokesperson said via email. “Public posturing about potentially bringing a meritless lawsuit against CrowdStrike as a long-time partner is not constructive to any party. We hope that Delta will agree to work cooperatively to find a resolution.”

Delta says it had nothing to add beyond the comments made by company CEO Ed Bastian during an interview with CNBC on July 31. Bastian says Crowdstrike didn’t offer any compensation for the outage.

Crowdstrike wrote in a blog on July 25 that the cause of the outage was related to an update it released to Windows systems. The update proved to be faulty and started a chain reaction of systems not working properly unless it was a Mac or Linux. Crowdstrike says the issue was resolved when it reverted the update Friday morning, but the damage had already been done.