Amending 2021 due to missing 1099 B crypto

[ConfusedMomma]

We filed our taxes seeing that we had a loss on our crypto so we didn't think it was important since it was small.   Unfortunately we were not aware that crypto companies only file the sales and not the original cost.   So buying and selling the same 3000 over and over made them think we had sold 20000.   They now want 4000 for that 20k they think we made.   I am trying to import but the import code/account and ID are the same as the 2022 year.   When I try to amend it tells me the user does not exist for 2021.  I have no clue what to do.   Can I just type in the summary of the sales and cost?

[fanfare]

"I have no clue what to do."

you know exactly what to do.

enter a 1099-B with proceeds 20,000 and cost < your cost>

enter date sold 12/31/2022 and date acquired "Various"

use Box category "C".

description: cryptocurrency OR "bitcoin" OR <some coin you trade>

you're supposed to enter with description the number of coins traded, but I'd leave that out .

@ConfusedMomma 

[fanfare]

"crypto companies only file the sales"

Did you get a 1099-B?

If so, use the box category that the document shows.

@ConfusedMomma 

[fanfare]

did you get a 1099-K instead of a 1099-B ?

I'm confused as to how the IRS knows you sold $20,000 crypto but you did not notice $20,000 of taxable gains on your tax return.

@ConfusedMomma