Why are the sales proceeds and/or cost basis so high on my 1099-B? Way more than actual value?



I filed a 2018 return and did not think it was an issue, but now it is an issue.

My son got an early admission from a private college and the Financial award was nothing. We were shocked and visited the Financial aid office. They explained that the proceeds and/or cost basis was over $500K and it was counted as our asset. 


This is what happened. had $40,000 of the available fund and I used margin to trade stocks multiple times.

IN 1099 all my multiple trades are totaled and made cost basis and the proceeds over $500K.. but in reality, I ended up losing $10,000 loss and I think  $500K was never in my account and was not an available asset at all.. Is there any way to explain this to the FA office and ask the reconsideration of the FA award?