Possible ear mites?

So we noticed Molly has been itching and shaking her head recently, we noticed she had a little bit of dark brown almost black gunk in her ear, so we took her to the vet today, he dismissed ear mites and just gave us some ear drops, i came home and looked up ear mites on the internet and she has all the symptoms, is my vet wrong?

I'm not sure if your vet could be wrong, but I hope the ear drops work for her......

I use thornit, it also kills ear mites Fab stuff x