How do you know s2z does not work? Do you get an error message, and if so, what?
The input to s2z must be complex numbers, in the form Re + i*Im. The file you provided has a header line and three columns: frequency, real part, imaginary part. It uses two different separators: tab and comma. That is annoying because it complicates the reading in of the data.
I assume that the data is in real, imaginary format. Change it to complex:
Then use s2z.