Did you have an amount on 1040 line 30? You tried to claim the Stimulus again. Did you enter the right amounts you got in the right boxes 1 & 2? You had to enter what you already got to see if you qualify for more.
But you already got the 600 separately so the IRS took it off your return. It should not have been on line 30. They know they sent it to you. Does that clear it up or do you still have questions about it?