Money bug

So when I sold my huracan on the auctiaon, some one bought it for 300,000 cr and when I collected it I got -300,000 cr what the heck!

When someone buys a car from you on the Auction House those credits don’t get added to your total credits UNTIL you collect the credits.

Auction house takes a percentage of every sale so yes, you will not get the full amount.

No, Im saying that i didnt even get some money the game took, 300,0000 from me

You clearly explained your problem in your first post.
Forget about reply #2 and #3.

It’s a known bug. Happened to others too.

If you want your CR back you need to open a support ticket:

https://forums.forza.net/turn10_postst132742_New-Support-Page.aspx