I have been using your product for several years on my 4.5 lb Yorkie. I purchased a box from //tractor supply on 7/05/2021. I put a tube on her the day I got it waited 3 days before bathing her. I also treated furniture and the yard. I discovered a flea on her 2 weeks later I gave her a capstar pill I waited until 8/12021 to put it on her again, today she has a flea on her. I don't understand. I have used it with no problems before I'm at a loss what to do, I can't put anything else on her now????? User's recommendation: I received no response.