Well, first off, welcome to the forums.

Ok, lets see.. How long have you had the ball python? How many days have you given it to rest completely without interruptions, and how many days inbetween attempted feedings? It sounds like this is a case of stress. I'm sure you are not sure if the snake is CB or an import, no matter what the people at the pet store tell you. And right off the bat, coming from a petstore, I am thinking it is probably at least CH, if not WC. So, if you can, try to get it to a vet to check for internal parasites, or if you know the dosage, do it yourself with some Panacur and Flagyl.

As with the mites, what did you use to get rid of them? I use Black Knight spray, and it has yet to fail me. I've also heard Prevent-a-mite was a good one, but I have never used it myself. They are both safe to spray and leave in the cage (even with the snake inside the cage, as well) without washing out. About 2 weeks after the first spraying, I spray again (just to be sure to get all the unhit eggs).

Pinkies are WAY to small for any ball python to be considered a meal; and live or freshkilled is the best thing to do if they are reluctant to take f/t. The most important thing is to get it to eat. But again, if it has only been a couple weeks since you received her, I would recommend you leave her be for about 2 weeks without picking her up or anything. Then try a live adult mouse. If she's hungry, she'll eat. And that should give her enough time to get "un-stressed".

It sounds like you are knowledgable about snakes, so good luck, and I hope I've helped some.
-Jennifer