Don't panic--ball pythons are seldom that 'regular' for their whole lives. They will often cease defecating when they're close to shedding. They save it up for right after the shed, lol.
Ain't that the truth???
Another trick...clean out the enclosure really well...sterilize everything and then put everything back in perfect, pristine order. You'll probably have a big ol' poop dropped in there within the hour.