I really feel you. Only a few months ago, I went through the exact same problems. I'll tell you all the things I've learned:
Humidity & Heating
1. If you have problems with humidity I might suggest you don't use Aspen. Aspen is a good bedding for ball pythons but it is a horrible humidity killer. From my personal experience I'd like to recommend cypress mulch. It's really great at keeping the humidity at a good level.
2. Maybe move the water bowl to the hot side of terrarium. That will keep the humidity up as well.
3. Problems with the heating due to the humidity are a bit more troublesome. I have a wooden terrarium. So if my terrarium gets colder than it's supposed to (for some reason) I like to put a blanket on the top but that's not a good idea if your vents are on the top. For the time being you can put a hot water bottle on the glass at the hot side (from outside).
Maybe a heat mat will be easier in your case.
Feeding:
Two weeks are almost nothing. You have to give your little worm a bit of time to get used to it's new environment. Maybe he hasn't eaten because he is simply stressed. It can take some time until new ball pythons start eating. Ball pythons also tend to refuse food if they are in shed so don't worry too much.
I personally put the mice/rat in some water (warm to the touch) and let it thaw out for about 20 to 30 minutes. If I don't fell any hard or really cold spots anymore, I take some hot water (like 60 degrees Celsius) and put the rodent in there for about 3 to 5 minutes. After that the rodent is normally warm to the touch. Then I feed my ball python with it.
Is your ball python used to frozen rodents or did he eat live rodents before you got him?
Furthermore there are cases in which the ball pythons are drop eaters. So they only take the food when you leave in there with them for some time. Maybe if the fast continues you can try that.