When you hit cancel amendment you also had to go back and remove all the changes made on the second amendment. You should also wait to mail in a second amendment until the first one has fully processed and you get the bill for the balance due.
Hopefully you saved a copy of the original return and the first amendment so you know what they look like because the second amendment's column A must start with the figures on the first amendment's column C.
Then you will manually have to adjust the amounts on lines 16 - 22.