I am creating a module to save the AC voltage from a simulation.

I used this code in my AC analysis and it reports the DC voltage instead of the AC. I need to get magnitude and phase or the real and imaginary parts.
Can someone help me with this?

if (analysis("ac")) begin
     $display("freq = %4.2f. v1 = %4.2f, v2 = %4.2f", $freq, abs(V(v1)), V(v2));
end

Thanks