I called them back during hours (using *67 to block my number). I hear 3 different style rings followed by, "the number you have reached is not in service. This is a recording." The inability to be called back is a major red flag.
I googled "GDIT". It stands for "General Dynamics Information Technology".
Here's my guess: this is another of the Microsoft Windows "problems with your computer" calls. They have also spoofed DELL phone numbers and Acquia (medium to large scale business computer solutions). I have called all 3, none of them actually called me. Using a real computer company name lends an air of legitimacy to their SCAM.
No tech company (including Microsoft) cold calls you. The scammers first want your money. Next they likely want online banking records, et al. which are on your computer for identity or regular theft. Often they install malware and then extort you for removal.