You want to be careful with some of the stuff you are advising here, sorry...but if any of you have lickers, like I do....some chemicals are toxic to pets. So, please, check with your vet before you use them.
I hope you had a few words with the groomer, and passed the word around about getting the fleas there. I learned to clip my girl's nails myself (and have the scars to prove it) after spending the money to have my vet's techs do it. Too many horror stories about the groomers everywhere. I had taken Daisy...the one in my avatar, to the groomer at PetSmart just once, and she was so freaked out that I made them stop.
Fleas are the absolute worst. You have to keep washing the bedding for weeks, same with the rugs, furniture, etc., until you kill all the fleas, larvae and eggs. Used the D.E. on your lawn. Get human grade, and you can add it to their food. It also gets rid of other pesky bugs. Be careful with garlic. DOn't give your pets raw garlic, ask your vet about that, it can be toxic to them. It's not the same as the pills.
I would go to the groomer and complain, and get my money back. At least get that much satisfaction.