We try everything.
We using hair nets. Clean uniforms.
But in Our pizza shop mostly ladies working.
How we can avoid hair problem.
Lots of hair spray or hair gel. 
I also have mostly ladies as well. Hats and hairnets work well for me.
I have had a couple complaints about hair. It turned out to be the way the cheese was cooking. It looked remarkably like a hair, but it was just a singed strand of cheese. I never questions a guest complaint about anything. I just make it right through refund, replacement, etc. However, I investigate the pizza later and the cheese issue was a real thing.