At a loss

[Big Gunns]

I'd say it was probably a preexisting problem. So, like others have mentioned, I'd stay in contact with the breeder.
In my experience, I've found ball pythons to be pretty hardy animals when given the proper conditions to thrive.
Also, quarintine and see the vet.

Not necessarily. If everyone hasn't noticed, BG usually comes to the defense of the breeder. Why is that? Because a million years of experience has told him that people NEVER EVER take responsibility when they do something wrong that causes a problem with their snake. It's ALWAYS the breeder/sellers fault.

Now...having said all that. In this case it may well be his/her fault, but it is your fault that you have waited so long to do something about it in all honesty Lilly....and now it may be too late. (sorry...BG tells it like it is) BG is gonna help yah now.

BG will now skip the 3rd person because this is serious.

Don't do anymore soaking. You need to get this snake to a QUALIFIED(HUGE emphasis on QUALIFIED) Vet asap....like now. When a snake regurgitates it's meal, it can be something simple....like the temps were not right...but it may be something else. I will usually treat a snake that does this with Flagyl, then wait a week or so and feed it a small meal. Sometimes you really need to "baby" them back with small meals for a while. It's much worse when a boa does this, but it can be just as lethal when a Ball does it.

You really need to get this snake to a VET NOW. Your snake may have already gone septic and it may be too late. Good luck to you, but don't do anything else but get your snake to a VET.....NOW!!!!!!!!