Does anyone have experience with this or know the protocol?

On Friday around 11am, I put Beaphar on my cat's neck. It's Saturday late afternoon and all the fleas are now on her back end, and they seem to be completely unaffected. They just relocated.

This Beaphar was supposed to be some "bio-organic" stuff but seems to be more like "doesn't do anything" formula.

I bought Frontline. Just researching to see if I should wait a few weeks or if I can follow-up with this in the next day or two.