Can you get the Method-1 PPS? It is pretty effective against mites. It is basically hemp oil and rosemary essential oils. If not, go buy some cilantro, bubble it in water for 24 hours with an airstone. Strain and mix it with your soap and spray the crap out of them: top, bottom, pots, everything!
Can you get neem seed meal instead of the oil? If so, you can use that the same soaking method as above. You can also use any oil. Horticulture oil is sold at nurseries, heck you can even use canola oil. Getting the oil to emulsify is tricky. I use Pro-TeKt to emulsify my oils. Add four ounces of oil, two tablespoons of Pro-TeKt and stir until the oil turns white (technically you are making soap here). Slowly add to a gallon of warm declorinated water.