Auction house mistake

I created an auction for titanium powder in the auction house. I sold a stack of 20 pieces with the intent to sell at 95g ea and an additional 13 pieces for 100g ea. After I clicked the create auction button for the stack of 20 I noticed my mistake of selling the entire stack for just 95g immediately. However, a user instantly purchased them. This user was not online a the time so I am unsure how they were even able to purchase the item, as I immediately messaged them to inform about my mistake.

Is there anyway to cancel or fix this issue? Unfortunately I'd be out nearly 2000g from the mistake, which I know was mine. At the very least, the user may have been using a bot to complete the purchase and I just want to be able to protect those in the future from it.

No, you won't get anything back.