It seems that Bungie has enabled a very strict, no holds-barred permanent account-banning system with Destiny 2, which will ban you if you are using any type of application that has hooks / overlay features. This includes Twitch, Discord, XSplit, GeForce Experience, NZXT CAM, Corsair Link, etc. When using these applications with Destiny 2 the message screen, “Not so Fast”, indicates that players have been banned, without forewarning or any further explanation.
People are freaking out on Bungie’s official PC Support forums, where there are many threads started by banned users. In some cases players were even banned before entering the character creation screen. A post from a Bungie forum moderator did not help the situation really, “In Destiny there are account restriction and bans,”, Bungie moderator “Kellogs” writes. “Restrictions are only temporary but must be waiting out while bans are permanent. Please note that Bungie will not discuss or overturn account restrictions or bans.”
The same Bungie moderator said that some apps might be incompatible with Destiny 2. So using them would result in the game not launching, but the user would not be banned. Many users have called this an outright lie. Many users have just been banned instead of the game not launching for instance.
Now if you’ve bought a digital battle.net key for the game you might have luck requesting a refund from Blizzard support, but if you bought a physical version of the game you are probably out of luck.