Need advice please! Vet/flea related.

[angelish]

As above there is no known resistance to frontline combo. Frontline and Frontline combo are different products, with the normal frontline being the one that doesn't work. I have been told recently by a rep for stronghold that it can take up to 3 months to break the cycle? So applying the product every month is key, and treating the environment.

If you are concerned the frontline combo hasn't worked, I would just ring up and ask for a different product, advocate or stronghold is what I use. Otherwise if your house is literally over-run with fleas....you may have to think about fumigating?

this ^
i took in a stray cat infested with fleas and lice , she was crawling with them , so much so that i didn't expect her to make it as she was very weak from lack of food and so many critters
it took a couple of times to get rid of all the fleas, the lice left the first time but the fleas took a second time to rid them all

i'd still speak to your vet as someone else has said they also need to know that it isn't working regardless as to weather or not they are going to compensate you