Hey Turtlx,
I've checked the logs and looked at the auction house bids at that time and it seems like you've initially bet $90,000,000 and later on increased your bet *to* $100,000,000 which means you only paid $10,000,000 when you placed your second bet. Given the fact that you were paid back $100,000,000 when you re-claimed your cash the system seems to be working as intended. I hope you enjoy the rest of your day.