Ok, thanks for the picture.
The one thing I cannot tell with the picture, is whether the switched wire is on the correct position, because they are all black in color.
Many times, the electrician will use a 3 wire that has a red and the red will allow distinction..
If you put the wires exactly back on the top and bottom side, they should be ok.
But if they are crossed, then the remedy will work still, but we may have to determine which 2 blacks actually go together on the bottom or top.
See the picture below, you need to remove the brass tab that joins the top and bottom BRASS screws only. Do not touch the silver screw side
It will snap right off with a couple twists with pliers.
That is how you switch the top or bottom and keep the other half powered, the wires alone then control power, where the tab in place will connect power to both top and bottom all the time.