Irony In Grand Theft Auto As GTA Online Bug Permanently Deletes Owned Vehicles
In GTA Online, you can't just steal any car off the street and throw it in a garage to keep it forever. You can actually steal some cars off the street, but if you want to keep it, you'll have to insure it. That way, when it gets destroyed, you can claim another copy of it from the insurance depot. All of the nicer vehicles will have to be procured from in-game web shops, and those purchases will be protected by default.
Vehicles in GTA Online can represent tens or even hundreds of real hours of work. The game is notoriously grindy, and while you can alleviate the grind somewhat by setting up in-game illegal businesses and running valuable multiplayer heists, the point is that players will inevitably get fed up with the grind and spend real money on "Shark Cards" that fill up your in-game wallet.
If you don't succumb to the urge and don't already have millions to spend on establishing a weed farm, meth lab, document forgery business, and a coke factory, then coming by the additional millions or tens of millions of "GTA$" that you'll need to spend to outfit some of the high-end vehicles in the game is a task that will take you weeks if not months.
Losing such an investment of time is a real bummer, but some players have apparently at least gotten their money back by filing a support ticket. If you've lost something due to this bug, head over to Rockstar's Support page and see about getting your due.