I am a 'no pesticides' kind of guy but one thing I have heard over and over when fighting mites is that you need to rotate products. The mites build an almost instant resistance so rotating from one pesticide to the next is highly recommended. And, repeat spraying is also an absolute. they breed so fast and most poisons don't kill the eggs. So, repeat spraying is required.
I am fighting mites right now and I am experimenting with fighting them with sound, UV and IR light, ozone, CO2, smoke, and as a last resort, I am going to try non-stop rap music. LOL
So far, ozone looks like the winner for effective and complete eradication of mites. Be very careful with ozone. It is deadly to humans (and your dog) just like it is the mites.