There are varieties of mites that are resistant to all of the above recommended remedies. For these, you need an expensive miticide such as Avid. See
Avid Miticide, Avid 0.15 EC Miticide Insecticide
I also advise you to either add a good surfactant such as Triton X-100, 2 ml./gal. or the pheromone, Stirrup M, which attracts mites to the dried droplets of Avid solution. See
Troy Biosciences (I can't find a store)
Triton X-100 Detergent | TALAS
If you don't follow my advice, I bet that you will fail.