Incorrect 1099-B Reported by brokerage

[t1krzej0]

Nadex has reported my 1099-B incorrectly, How would I report this to IRS as they are not evening bothering to check/help?

[KeshaH]

When entering the 1099-B transaction, if you need to adjust your cost basis check the box that says that your cost basis is incorrect. You will be asked about the adjustment you need to make.