Hope you are still around. I had to check with some other Ball owners because balls are not my strong suit.
I learned that Ball Pythons regularly go on fasts and that this is a common time for fasts. Fasts can last from 2-12 weeks. So continue to offer food every 3-4 weeks and then start a regualr feeding schedule again. Suggested every 7-10 days.
Something else to consider is that your python might be stressed. If you are housing your pythons together, the one not eating might be stressed by the other snake. It would be better if they were housed in
separate cages if this is the case. If that is not an option, make sure you have several SMALL and TIGHT fitting hide areas.
You also should check the cages temperatures. You want temps to range from 78 deg F on the cool side to the mid 80's on the warm side and a localized basking area that reaches 90-92 deg F.....these are the ambient temps, that is, the temps that occur not only on the floor of the cage but the "air" temp of the cage).
Hope this helps.