If you reported the loss amount correctly, then you should have nothing to worry about. It may be that the IRS received a 1099-B form indicating a gain that does not reflect what actually happened. For instance, the cost basis might be missing on the 1099 form or it may be wrong.
I suggest you research the matter and create a schedule that shows what you paid for the investment, what income or losses you reported each year from the investment on your tax return, if any, and the resultant tax basis of the investment when you sold it. The sales proceeds less your adjusted basis will be your deductible loss, and if that agrees with what you reported on your tax return, the IRS will adjust their records accordingly.
You may not need to amend your tax return if your reported loss is correct. In this case, you would simply need to correspond with the IRS and demonstrate that your reported loss on the tax return is correct.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
